Duntov’s New 1963 Z06 Corvette Sting Ray Battles Shelby’s New 289 Cobra and WINS!
Dateline: 6-3-22 This story originally appeared in the February 2008 issue of Vette Magazine
Introduction: The C8 Z06 has just about taken all the air out of the room when it comes to talking about Corvettes. The April 28, 2022, Michelin Corvette Bash at the National Corvette Museum was astonishing. Engineers from Michelin and the Corvette team were on hand presenting seminars loaded with technical information about the new C8 Z06. A week or so later, Team Corvette teased fans with a 30-second teaser of the 2023 Hybrid All-Wheel-Drive Corvette that will supposedly be released in 2023. Continue reading “Z06 Corvette Review, Pt 2 – The ORIGINAL Z06 – the 1963 Z06 Corvette”→
Dateline: 4-5-22 (this story was first published in the April 2018 issue of Vette Vues Magazine) –The term “GT” is arguably one of the most misused automotive designations. The term dates back to the 1930s in Europe and is an abbreviation for the words “grand touring,” or as they say in Italian, “Grand Turismo.” In the classic sense, a GT car was a road-going, lightweight, semi-luxurious coupe, built on a high-performance chassis. In the 1960s, American carmakers started to apply the GT term to many of their new pony and intermediate-size cars.Continue reading “Mike & Linda Waal’s Grand Touring (GT) 1980 Corvette”→
When it Comes to Grand Sport Replicas, Attention to Details Pays Off!
Dateline: 2-1-22 This story was first published in the February 2019 issue of Vette Vues Magazine –Larry Taylor’s passion for Corvettes might be genetic. The Clinton, Utah resident’s grandfather was into Corvettes in the 1950s. Grand Pop passed down his Corvette passion to Larry’s Dad who owned a 1966 Sting Ray that he drag raced a little and also used to trailer his boat. When it came time for Larry to enter the world of automobiles, his first Corvette was a 1959 model that he bought in 1984.
Larry has an affinity for details. Anyone who has ever gone after an NCRS Top Flight award knows it’s all about “details, details, details”. It wasn’t long before Larry’s 1959 Corvettescored a Top Flight award. Classic Corvettes are wonderful, but as the 1990s went on the C4 Corvettes were looking better and better. So in 1995 Larry decided to get a “modern” Corvette and bought a 1990 Corvette. The C4 was really nice, but he found himself pulled back to the classics. Larry sold his 1990 Corvette, but not before acquiring another NCRS Top Flight award. If your passion is classic Corvettes, you can’t get much more “classic” than a 1963 Split-Window Coupe, which, you guessed it, Larry got another NCRS Top Flight award.
While all this was going on, Larry did some open-wheel racing and always liked Corvettes with racer-style. So if you are into “racer-style” and you own a 1963 Split-Window Coupe, it is no stretch that you would be drawn to the 1963 Grand Sport Corvette; the greatest “could have been…” Corvette of all time. If you are new to the Corvette hobby you might be wondering, “What’s so special about a Grand Sport Corvette? It’s a nice model Vette, but what’s the big deal?” Well, we’re not talking about the 1996 Grand Sport, or the C6 and C7 Grand Sports. No, we’re referring to the 1963 Grand Sport Corvette all-out racecar; arguably THE most storied car in Corvette history. Here’s the short version of why the Grand Sport is still being talked about, longed for, and honored with the production and replica Grand Sports.
In early 1962, after the major engineering work was completed on the new, upcoming 1963 Sting Ray, Zora Arkus-Duntov and his team got to work on RPO Z06. Duntov’s C1 racer kit program was hugely successful, such that by the end of the 1950s and into 1962, Corvettes were a force to be dealt with in SCCA racing. The Z06 was to carry on with Duntov’s program. That is until Carroll Shelby’s 2,000-pound Cobra arrived.
Duntov was an experienced racer and he knew that his 3,000-pound Z06 Sting Ray would be no match against the 2,000 Cobra. To Duntov, it was obvious; he needed to build a lightweight Corvette and to do this if would have to have a tube frame, an exotic engine, and a lightweight replica body. But what he really needed was official permission. Fortunately for Duntov, he had a friend at the top of Chevrolet; Semon “Bunky” Knudsen.
Knudsen was a serious “car guy” corporate officer who worked his way up through the ranks at GM. As general manager at Pontiac, he turned the brand’s stodgy image around with his Wide Track, Tri-Power performance cars, and factory support in NASCAR racing. His reward for doing a great job at Pontiac was the general manager position at GM’s flagship division, Chevrolet in 1961.
Knowing he had Knudsen’s ear, Duntov outlined his plan to get around GM’s adherence to the 1957 AMA Racing Ban. Duntov’s idea was to build limited production lightweight Corvettes that would sell for around $16,000-to-$20,000 and let the customers do the racing. Knudsen green-lighted Duntov plan and five, special cars, called, “The Lightweights” were built.
By November 1962 cars were completed and were renamed “Grand Sport”. They looked almost exactly like the production Corvette, but with minor differences and no split rear window. Initial testing at Sebring in December 1962 was very promising. But when word of Duntov and Knudsen’s covert activities reached GM President Frederick Donner, the Grand Sport came to a screeching halt! Documents at The GM Heritage Center indicate that the five Grand Sports and the spare parts were ordered to be warehoused, but that didn’t last long.
Duntov gradually loaned out Grand Sports #003, #004, and #005 to privateer racers. But without a proper development program, the cars were not successful and their performance was inconsistent. By the end of the racing season, Duntov called in the three Grand Sports for a few “improvements”. Duntov wanted to give his Grand Sports a fighting chance against Shelby’s Cobras at the upcoming 1963 Nassau Speed Weeks race at the end of November and the beginning of December.
When Grand Sports #003, #004, and #005 arrived in Nassau under the banner of the “Mecom Racing Team”, they were loaded for bear. This is the now-classic Grand Sport look; fat racing tires on wide knockoff wheels, aggressive vented hood, and big wheel flares. And under the hoods were Duntov’s latest engine jewels, the all-aluminum 377 small-block Chevy with 58mm side-draft Weber carbs. It was a romp for the grand Sports, as the Cobras were thrashed.
Three months later, the 1964 class win at the 12 Hours of Sebring with Roger Penske at the wheel of Grand Sport #005 would be the high-water park for the Grand Sports. This time period saw extraordinary advancement in racecar technology, such that by the end of 1965, the three-year-old cars were outdated.
When the Grand Sports received their upgrades in preparation for the 1963 Nassau race, Grand Sports #001 and #002 were made into roadsters and held back, but were eventually sold and raced, as were the coupes. Fortunately, all of the cars survived, are in excellent condition and are each worth millions of dollars. Over the years, Grand Sport Corvettes have thrilled thousands of fans, many have lusted to own one of the five cars, and around two dozen have actually owned Grand Sports.
Enter the world of kit cars. In early 1990 a company called D&D started making Grand Sport kit cars, but the quality was not good. Mongoose Motorsports offers high-quality 1963 Grand Sport and 1980s era GTP Corvette kits and turnkey cars. Then there are the Duntov Motors Grand Sport Continuance Racecars and the Superformance custom built-to-order Grand Sport cars.
When Larry decided to merge his interest in classic Corvettes, racing, and his attention to detail skills, he decided to go for a Grand Sport replicar. The Superformance Grand Sports are fantastic but on the expensive side, so Larry decided to get a Mongoose Grand Sportroller and finish it himself.
When you buy a Grand Sport roller from Mongoose you get the bare fiberglass body and interior, and a 4-inch tube chassis and basic suspension from a 1988 Corvette. The rest is up to you and your skill level. Larry bought the rolling chassis in April 2016. Many Grand Sport replica cars are finished as street machines with modern paint, wheels, tires, and amenities. A few are street versions of the real Grand Sport replicars. If you are going the racecar replicar route, you have to research which livery you want to replicate. Since the three Grand Sport coupes were raced by numerous owners; in different configurations; and liveries; one has to do their homework; and pay attention to details. Fortunately for Larry, he’s very good at that. After careful research, Larry chose the Sebring ’64, Delmo Johnson, and Dave Morgan livery. Today the actual car is part ofThe Reve Institute in Naples, Florida.
An all-aluminum 377-cubic-inch Donovan small-block Chevy engine with four Weber 48-mm side-draft carbs powers Larry’s Grand Sport. The real small-block Grand Sports used 58-mm Webers, but they are insanely expensive. The side exhausts are hand fabricated. The radiator, oil cooler, and power brake booster are 1963-style. The transmission is an M22 4-speed “Rock Crusher” and the shifter is an original 1963 shifter.
The front suspension is from a 1988 Corvette and has rack & pinion steering. The rear suspension is somewhat unusual. It is a modern coil-over suspension that uses the C4 differential and “batwing” rear cover and carrier. For an authentic look, Larry added a set of C2/C3 leaf springs and painted the batwing differential carrier black.
The wheels are 15×8 Halibrand aluminum replicas that have been powder-coated gold. The real Halibrand cast magnesium wheels had gold Dow 7 Magnesium Coating. When the real Grand Sports were racing they used then state-of-the-art Firestone racing tires. Larry’s Grand Sport replica uses 15×8 period-size correct Goodyear racing tires. As mandated back in the day when the Grand Sports were racing, there’s a spare tire in the “trunk” area.
“font-size: large;”>As delivered, Larry’s Grand Sport interior was bare fiberglass. Larry added some extra bolsters to the fiberglass seats, period-correct seat belts, a fire extinguisher, and a period-correct CB radio and antenna. The speedometer has been fitted with a 200-mph speedometer face and the factory fuel gauge has been replaced with an oil temp gauge. The toggle switches control the main fuel pump, differential cooler, and reserve fuel.
With a ton of photographic references for the Grand Sport #004 that currently resides at the Collier Museum, Larry applied his attention to detail skills to his Grand Sport replicar. As seen in these photos, the car was just completed in November 2018. Larry’s plans for 2019 are to show the car at Corvette shows and maybe at the National Corvette Museum. Then, he will bring the car back into his shop, remove the body, add all of the required modern safety equipment, and then take the car to the track.
The Donavan 377 small-block Chevy engine pulls around 550-horsepower, so weighing in around 2,250-pounds, that’s a power-to-weight ratio that will be a lot of fun on the track. Larry says, “I just want to have the experience of being on a race track with my Grand Sport and other vintage cars, just to be there; not to race and win anything, but just to get a sense of what it must have been like back in 1964.”
That’s something I believe we have all fanaticized about Larry. Go for it! – Scott
Dateline: 8.29.21 This story was first published in the February 2021 issue of Vette Vues Magazine; Story by K. Scott Teeters; Photos by Mario Brunner: In the Corvette world, C2 Sting Rays are becoming increasingly rare. With only five years of production, 1963-to-1967, only 117,964 Sting Rays were built. Compare that figure with the 1968-to-1982 C3 Corvette total production of 542,741. Now imagine a 1966 Sting Ray convertible in modern-day Germany in an ocean of Porsches. Let’s add another layer of uniqueness. Mario Brunner’s 1966 327/350 Corvette convertible is a numbers-matching pilot car!
Before we get into the details of Mario’s unique Sting Ray, let’s review pilot cars. After the details of an updated car are nailed down, a small batch of cars are built for evaluation. Engineers drive the cars to make sure everything works, everything fits properly, no leaks, etc. The cars are not subjected to harsh durability testing, they are driven as a customer would drive the car. Pre-production cars built for durability testing are typically pretty-well beat-up and are eventually sent to the crusher. When you see magazine road tests that come out before or at the same time as the new cars are in dealer’s showrooms, those are pilot cars.
Pilot cars are also built more slowly so that the plant workers can make sure that everything is up to speed for production. As problems are identified, solutions are implemented. Typically around 20 pilot cars are built. Pilot cars can be identified by their very low last three VIN numbers. Any VIN number 001 and above is considered by GM to be saleable.
After evaluation, pilot cars are sold at the GM factory auction to dealers. Pilot cars are not the same as GM Fleet / PEP cars, private fleet cars, or dealer demo cars. Pilot Corvettes have a unique place in Corvette-Land, while they look like a regular Corvette, they are quite rare.
I recently read a humorous expression for us “car people”; we’re the way we are because we have “the car gene”. Mostly guys have it, and some gals too. Typically, the car gene kicks in during our adolescent days, around the ages of eight-to-ten. All races and nationalities can have the car gene.
Mario Brunner grew up in the small German village of Enzweihingen, just northeast of Stuttgart in southern Germany. As a little boy, his family often drove into Stuttgart and would drive by the Porsche factory. Today, the Porsche factory and museum are at the same location. Mario recalls, “I was absolutely fascinated with the Museum and the beautiful Porsches parked in front of the museum. It all started there. My dad was also a car and motorcycle guy. He owned a Harley and some Jeeps. When he passed away way too soon, my mom told me, to maintain dad’s legacy, I had to buy a classic American car.”
When Mario grew up he became a professional photographer. But Mario’s intense car interest was a little out-of-the-ordinary in a European nation; American muscle cars were his passion. At the top of Mario’s bucket-list was a 1963-to-1967 Corvette Sting Ray. In 2010 Mario acquired a 1967 383 stroker engine Camaro and in 2017 Mario bought a 1964 327 4-speed Impala SS. But he still had the Sting Ray itch, and we all know what that’s like. Mario was definitely on the hunt and the car he found is truly extraordinary.
On Craig’s List Colorado, Mario found the car of his dreams; a 1966 327/350, 4-speed Sting Ray convertible with factory side-pipes, knock-off wheels, and a hard top. Much to his surprise, the car was a pilot car with the VIN #194676S100006. Note the last three numbers, “006”, that’s what tipped off Mario that the car is a pilot car. Mario sent NCRS detail photos of the car and they verified that indeed, Mario’s Corvette is a “pilot car”.
NCRS’s 1966 specialist told Mario that the car is very early and rare pilot car and they were very impressed. Concerning the authenticity of the VIN plate and the Options plate, NCRS said that the rivets and the arrangement of certain letters indicate that the tags are legitimate. Another indication that the car is indeed a pilot car is the hand-laminated fiberglass inner fenders in the engine compartment.The inside of the front wheelwells look completely normal.
As if the pilot car status wasn’t enough, the car is numbers-matching, complete, all-original, and well-optioned. The car is a survivor and in 2009 was treated to a new Laguna Blue respray. In 1966 only 2,054 1966 Corvettes were ordered in Laguna Blue; only Trophy Blue (2,054) and Tuxedo Black (1,190) colors are rarer.
The car was optioned out to be a maximum-performance small-block 327 Corvette. The L79 327 engine was rated at 350-horsepower @ 5000 rpm and 360-lb-ft of torque @3000-rpm. The next step up the 1966 Corvette performance ladder was the L36 427 with 390-horsepower and then the L72 427 with 425-horsepower. If a lighter-weight Corvette with plenty of grunt was your passion, the 350-horsepower L79 327 was a $105 option! The base price of a ’66 Corvette convertible was $4,084 and Mario’s car had a sticker price of $5,573. That was a lot back then!
A closer look at the options on Mario’s ’66 Corvette indicates that the car was optioned for performance. Options include: L79 327-cid, 350hp Engine, M20 4-speed Manual Transmission, Side Mount Exhaust System, Power Brakes, Positraction Rear Axle, Cast Aluminum Knock-Off Wheels, Genuine Leather Seats, Soft Ray Tinted Glass, Telescopic Steering Column, Teakwood Steering Wheel, Power Windows, AM/FM Radio, and an Auxiliary Hardtop.
Missing from the option list were Air Conditioning ($412, the single-most-expensive option in 1966) and Power Steering ($94). But if the car was optioned for maximum small-block performance you wouldn’t add unnecessary weight to the very front of the car. The tires are Goldwall Michelin 215 Radials with the tire information on the inside of the tire to maintain a classic look.
In 2019 Mario decided it was time to go for his dream classic car, a Corvette Sting Ray. He sold his ’67 Camaro and ’64 Impala to fund a C2 Corvette. So when Mario found a super-clean, complete 327/350 ’66 Sting Ray on Craig’s List Colorado, he knew others would be looking at the car, so he had to act fast. Mario says, “I haven’t owned the car that long. After being transported to Germany, when the trailer opened and I saw the car for the first time, it was a very emotional moment. Unreal. Mileage is low, with just 65,585 miles on the odometer.”
Mario did some research on the car’s build and found several interesting things:
* The 1966 model year production started in September 1965. This car was built on 9th
July 1965. Body number 5.
* The car has hand-molded inner fenders.
* The engine block has the correct casting number for 1965 models (3782870) but the
correct serial number for Corvette number 6 of 1966. Engine, distributor and cylinder head
were made on 24th May 1965.
* Lot of early 65 parts.
* New color for 1966, perhaps the first 327 convertible ever painted in Laguna blue.
Back in the day, cars such as Mario’s were often driven very hard. I’m certain that somewhere in the car’s past it was driven “with enthusiasm”, but the car is 100-percent complete and numbers-matching and shows no signs of being thrashed.
Mario explains, “Most people that see the car don’t know what it is because there are hardly any C2 Sting Rays in Germany. Germans know what Mustangs are, but not old Corvettes. They also can’t believe a car this old has 350-horsepower. The ultimate pleasure is to drive the car without the top on a warm summer night, listen to the side-pipes, feel the 350 hp V8, and knowing that this is a very special car, especially here in Germany. This is the fulfillment of a life-long dream for me. It’s a privilege to drive something special like this.”
“The only repairs I had to make was replacing the intake manifold gaskets, shocks, flywheel, and clutch, that’s it. I drive the car as much as possible. It is pure joy and adventure to drive. NCRS recently confirmed that the car is indeed one of the rare pilot Corvettes. For me, this is the best and last classic car in my life.”
When asked what he intends to do with his 1966 327 Corvette Sting Ray pilot car, Mario gave the right answer, “Drive it. Take care of it, and learn more about the car’s history.” Yes, spoken like a man with the car gene! – Scott
PS – Mario Brunner is a professional wedding photographer in Stuffgart, Germany. Check out his work HERE.
PSS – To subscribe to Vette Vues Magazine,CLICK HERE.
Car magazines were my friends when I was a young teenager in the late ’60s. While I was crazy about Corvettes, there were no road racing tracks, only a drag strip close to where I lived in Collingswood, New Jersey. So, if I wanted some racing action, the drags was it; which was fine by me because tire-burning muscle cars regularly roamed the streets of our town, and were SO COOL.
Zora and his brother, Yura were making and selling their Ardun hemi-head conversion kits for flat-head Fords in the early 1950s.
Hi-Performance CARS, Popular Hot Rodding, Car Craft, Car and Driver, Car Life, and Hot Rod Magazine were my favorite flavors for fun reading. But somehow, the December 1967 issue of Hot Rod got past me, as I did not see that issue until way after eBay sellers started selling them 20 years ago. Recently I picked up a copy to add to my Corvette library.
The BIG SPLASH is the cover! There was Zora on the cover of Hot Rod, in a corporate gray suit, white shirt, a narrow black tie, and all smiles; but then again, Zora never knew a camera he didn’t like. And why wouldn’t he have been a happy guy, sitting there with four exotic experimental Chevrolet engines; single-overhead cam heads, and double-overhead cam heads with fuel injection systems of different configurations. Duntov even pushed to offer a SOHC kit for small-block Chevy engines via the Chevrolet Parts Catalog! Imagine that under the hood of your Vette!
Hot Rod’s editor, Jim McFarland got the plum assignment to go to Detroit with a recorder and interview Duntov about “some” of the experimental engines Chevrolet engineers were playing with. After the sixth paragraph, McFarland turns over the mic to Zora to take it from there. Duntov was very exacting and articulate in explaining everything he was allowed to talk about. Zora may have been the ultimate corporate misfit in his time, but he knew when to stop talking.
Here’s Zora and Jim McFarland many years after the famous Hot Rod Magazine “Inside Chevy’s Secret Engines!” December 1967 cover story.
The article is a fascinating peek inside the thinking of Chevrolet performance engineers, circa 1967. Enjoy! – Scott
Before the 1969 427 ZL1, there was the All-Aluminum 377 Small-block Chevy!
Dateline: 5-7-21, This story by K. Scott Teeters was first published in the October 2019 issue of VETTE magazine – In the early 1960s, an aluminum performance engine was as exotic as fuel injection, independent suspension, and four-wheel disc brakes. The first mention of an all-aluminum engine for a Corvette was in Zora Arkus-Duntov’s proposal outline for the Q-Corvette in 1957. Ed Cole was Chevrolet chief engineer from 1952 to 1956 and was the lead engineer in the design and development of the small-block Chevy.
The Wintersteen L88 Grand Sport #002 resides at the Simeone Museum in Philadelphia, PA. Part of the collection includes the hand-made #002 Roadster replica body and one of the all-aluminum 377 SBC engines that Dr. Simeone purchased from Jim Jeager. The replica body is mounted to a chassis buck with an interior.
Cole was a mechanical engineering visionary. After he became Chevrolet’s general manager in 1956, Cole announced his 1960 Q-Chevrolet concept that would put a transaxle into every car to improve traction and handling and eliminate the transmission hump that would open up the interior. Cole’s plan included the Corvette.
Even before going to work for Chevrolet, all Duntov wanted to do was to build racecars. Based on his racing knowledge, Duntov’s Q-Corvette was spectacular and included; a four-speed transaxle, four-wheel independent suspension, four-wheel disc brakes, and an all-aluminum fuel injected 283 engine. Duntov is usually credited with the all-aluminum small-block Chevy, a deeper look tells a slightly different beginning.
The design parameters of Cole’s SBC were that the engine should be; small, lightweight, simple, and inexpensive. Cole reasoned that an aluminum version of the SBC using a new aluminum-silicone alloy would be obviously lighter and probably less expensive to make. To keep costs down, there would be no valve seat inserts, no pressed-in valve guide inserts, or cylinder liners. But sometimes a simple idea turns out to not be so simple.
Problems started right from the beginning. The complex molds used sand cores and the completed castings required extensive machining. Sand-cast aluminum is high in porosity and low in density. During machining, cavities would open up in the castings, causing a high rejection rate, which drove up the cost.
Another indication that this is likely to be one of the Nassau Invasion 377s is the chrome stamped steel valve covers. Photos in the “Corvette Grand Sport” book by Paddock and Friedman from the race show the same valve covers.
Aluminum pistons on aluminum bores were hard to lubricate and would scuff the bores. Between the strength of materials and the casting challenges, pouring aluminum into molds designed for cast iron wasn’t going to work for mass production.
Weber carbs were THE hot setup in the 1960s before fuel injection became more efficient. The 377 used four massive 58mm side-draft carburetors. The “EW” on the float chamber cover stands for Edoardo Weber, the founder, and inventor of the Weber carburetor.
A few aluminum engines were completed. Duntov installed one in his CERV-I car in 1959, but the valves would freeze to the guides when the temperature went low. Mickey Thompson got an aluminum engine for an Indy car project and bored the cylinders to installed steel sleeves to reduce the C.I.D. to the Indy limit of 255-C.I.D.
Note the non-stock location of the alternator. This was to slightly lower the car’s center of gravity.
Roger Penske had TRACO modestly build an aluminum SBC to just 300-horsepower for his Cooper Monaco. When TRACO was done, the engine weighed just 350-pounds; the lightest of all the aluminum SBCs.
Forensic evidence gleaned from the book, “Corvette Grand Sport” by Paddock and Friedman indicates that based on the shape of the collector on the headers, this was most likely one of the engines used during the Nassau assault in 1963.
The original SBC was never designed to be cast in aluminum. So when exact copies were cast in aluminum, the basic weaknesses of the original design were obvious. In 1960 some Corvette brochures offered 275 and 315-horsepower fuel injection engines with aluminum heads but were canceled early in production due to breakage. Briggs Cunningham was to be given several sets of aluminum heads for his Corvette Le Mans assault, but none were installed.
When Duntov started planning his Lightweight Sting Rays in early 1962 to battle Shelby’s Cobras, the SBC had 327-cubic-inches. Duntov insisted on an all-aluminum 327, reasoning that the heavy-duty parts from the L84 Fuelie would be more than enough for his racing engine. Unlike the previous aluminum engines, steel cylinder liners were pressed into the block. After each block was machined, it was water-tested for leaks. If leaks couldn’t be fixed with welding they were scrapped.
The most significant change to the basic block was that the main bearing webs were thicker and four-bolt main bearing caps were used. The earlier aluminum SBCs were not delivering any significant power increases, so it was decided that more cubic inches were needed. A 4.00-inch stroke yielded 402-cubic-inches. However, experimentation showed that the engine was happier with a 3.75-inch stroke that yielded 377-cubic-inches. Notches had to be made into the insides of the block for connecting rod clearance.
Numerous cylinder head designs were considered. The wildest was a hemi head design with two spark plugs per cylinder. The hemispherical combustion chamber allowed for larger 2.20-inch intake and 1.72 exhaust valves. The intake system was a Rochester constant-flow fuel-injection unit. This was Duntov’s preferred engine for his Lightweight but never was developed or tested. Engineers expected 600-horsepower from the 402-cubic-inch configuration.
The Mark II big-block with its unique “porcupine” semi-hemi heads was in development, so engineers designed and cast similar sets of aluminum heads for the SBC. Initial tests showed that they did not flow as well as the standard wedge combustion chamber heads, so the concept was dropped. If the heads had been developed they could have been a game-changer and made it into production cars.
Twelve aluminum 377 blocks were successfully machined and designated “A” to “L”. WhenJohn Mecum took delivery of three Grand Sport Corvettes as part of his Nassau invasion, the cars had aluminum 377s with four 58-mm Webers. After the Grand Sports stomped the Cobras at Nassau, the cars were bought and sold at a brisk pace.
Engineers learned that the aluminum 377s were good for short races, such as Nassau, but not durable for long races, such as Sebring. When Penske raced Grand Sport #005 at Sebring in 1964, his car was powered by a steel version of the 377 and performed very well.
Several of the engines were sent to Jim Hall and installed into his Chaparrals. Hall was instructed to install the engines and not to change anything except for timing and settings for the Webers. The engines were plugged in, raced, and returned to Chevrolet for evaluation.
The inscription of the transmission is unusual and indicates that it was likely to have been a specially built unit. “W.O.26310” could have meant “Work Order”. “TRANS #7-B” could have meant the second rebuild of transmission #7. Also note that the bolts on the case side plate are aircraft safety wired. A special team at Chevrolet built all of the 377 engines, the safety wiring was likely a deterrent to tampering.
As the engines were raced, eventually nearly everything either failed or upon examination was soon to fail. For instance, when one engine threw a rod, engineers used a new process for making rods called, Vacuum-Induction Melt steel to insure no impurities in the raw forging. When bolts were magnafluxed and showed signs of stress, all bolts were then over-designed. Rocker-arm lube was another issue and there were electrical problems with the early-transistorized regulators and ignition amplifiers.
Note the serial number on the back of the block casting, “0240983” and the casting date, “8-20-63”. This “could” have been one of the engines used in the 1963 Nassau assault in early December 1963 that stomped on the Cobras.
Exhaust headers were showing signs of cracking at the ports due to metallurgical problems. This was fixed by using a different welding process. Camshaft gears were failing when dry-sump oil systems were installed. Excessive stress and wear on the camshaft drive gear caused the distributor to retard the timing; causing a drop-off in power.
Privateers raced all of the Grand Sports and many changes were made to the cars. One of the previous owners of the Simeone 377 built this expanded capacity oil pan. Original versions of the engines used as many stock performance parts as possible
The perceived advantage of the all-aluminum SBC was weight; the complete engine weighed 150-pounds less than a cast iron version, however, the aluminum engines didn’t make quite as much power. Because durability was such a serious issue, in the early years, development work went into durability.
Eventually, the aluminum SBC reached optimum development, priced itself out of racing, and didn’t contribute any parts that went into production engines. Close to the end, there was talk of an overhead-cam kit for the SBC, but no action was taken. The amount of money spent on the program was an accounting nightmare for sure. At best, all the problem-solving saved years of development time for the all-aluminum Can-Am block and the ZL1. In a sense, the all-aluminum SBC was a prehistoric ZL1, domed by the basic “bread and butter” design of the original SBC. – Scott
Reproductions of this post’s lead illustration of the All-Aluminum 377 Small-Block Chevy and the Grand Sport #005 are available as 11″ x 17″ prints, signed and numbered by the artist, CLICK HERE!
And for fans of the 1963 Grand Sport Corvette, we have LOTS of Grand Sport Corvette prints CLICK HERE!
A Look Back At An Inexpensive Option That Delivered a Little Extra Grunt and A Lot of BARK
Note: This article was first published in the December 2013 issue of Vette Vues. Subscribe to Vette Vues HERE! –Corvettes enjoyed a banner year in ‘08. When no one was looking, GM unleashed the latest variation of the LS generation small-block Chevrolet engine, the LS3. This latest edition of the highly successful LS series of GM engines is only 12-cubic-inches larger than the LS2, but uses the Z06-style valves and port design that features larger and straighter intake ports, nine-percent larger valves, and a five-percent higher cam lift. For what wasn’t much of a stretch, the LS3 netted out an extra 30-horsepower for the base model Corvette, which added up to a whopping 430-horsepower for the base Corvette! But a close look down the ‘08 Corvette option list shows a little item called, “Dual Mode Exhaust System” (RPO NPP) for $1,195. This was the first time since 1969 that Corvette buyers had a factory exhaust system option.
This version of Corvette factory side pipes were available from 1965 to 1967
You could call it the Trickle-Down Horsepower Theory from the high-performance Z06. The Dual Mode option functions the same as the Z06 version. The outlet valves are vacuum-actuated to open during what Chevrolet calls, “high-load operation.” (That’s GM-speak for “get’n on it!”) While the Z06 version has 3-inch diameter exhaust pipes, the LS3 version uses 2-1/2-inch pipes. So, how much extra grunt do you get for your $1,195? The system adds 6-horsepower and 4-ft/lb of torque. While those numbers aren’t terribly impressive, the exhaust note certainly is. Of the 35,301 Corvettes sold in ‘08, 13,454 (38.1%) were equipped with the new system. That’s pretty cool, considering that’s only $199.16 per horsepower unit and $298.75 per torque unit, but we won’t quibble over numbers. After all, the system sounds great!
As these side pipes got older, they got louder.
It all got me to thinking about those infamous, barking side-pipes that were offered from ‘65 to ‘67, and slightly milder ‘69 side-pipes that made even the 300-HP small-block sound as ominous as a junkyard dog. Two unique designs were offered back then. Beginning in ‘63, as part of the overall Z06 package, was the $37.70 N11 option, the Off-Road Exhaust System, which included low-restriction, under the car mufflers and 2-1/2-inch exhaust pipes. This option was available through to ‘68 and was officially listed as “off-road.” (That’s GM-speak for “race track”, is in, racing.) The N14 Side-mount Exhaust System was another animal altogether. The system begins at the end of the exhaust manifold flange with the typical 90-degree bend.
Side pipes were not available on the new 1968 Corvette but were brought back for 1969 only. The side pipe setup was available through Chevrolet Parts Department for many years after 1969.
But instead of bending towards the back of the car, the bends were directed towards the sides of the car. After a short distance of about 12-inches or so, there was a gentle bend of approximately 118-degrees that leads to a long, straight tube that passed as a “muffler.” The “muffler” portion that ran along the side rocker panel had small crimps that created little internal baffles – and not much baffle at that.
Since Chevrolet didn’t want to burn the ankles of their Corvette customers and passengers, a set of beautifully styled, aluminum covers were designed. Each cover featured five horizontal ribs, with five sets of vertical blacked-out indentations between the ribs. The standard side rocker panel was replaced with a narrow polished aluminum rib that was mounted over the top of the covers. These hid the attachment screws that held the side covers. At the end of the piece of long, chambered tube was a downward-pointing chrome exhaust tip. And here’s the kicker… the Side-Mounted Exhaust System cost was only $131.65 in 1965! Plus, the system looked fantastic! Talk about “muscle.” Side pipes not only made ‘65 to ‘67 Corvettes look serious, they sounded serious!
The C3 side pipes look great on this black 1980-1982 model. Owners could not do this until the car reached “antique” status and was no longer subjected to emissions testing. In the side pipe system, there was no capacity for catalytic converters.
But as good-looking and inexpensive as they were, by the numbers, it wasn’t a terribly popular option. Only around 10-percent of all ‘65 to ‘67 Corvettes were optioned with the system. When the new Mako Shark II-inspired C3 Corvette came out in ‘68, the side-pipes weren’t on the options list. It was said that GM’s VP of Styling, Bill Mitchell, didn’t want to distract from the new shape with side-mounted exhausts. That may or may not be correct. It wasn’t that Mitchell was opposed to loud, side-mounted exhausts – nearly every concept and show car that came out of his studio had side-pipes as standard equipment. Considering what a nightmare it was getting the new Mako Shark II design out as a ‘68 model, perhaps there just wasn’t time for side-pipes.
This is Kevin Mackay’s “see-through” 1969 427 L88 Corvette. These mufflers were more like real mufflers, as they were not chambered pipe, like the 1965-1967 side pipes.
When the ‘69 Corvettes came out, side-pipe fans rejoiced over the return of the barking pipes. Only the new version didn’t bark as much. While the new pipes bolted on and functioned like their predecessors, the minimalist chambered pipe was replaced with a for-real muffler. However, the covers were beautifully styled to fit the unique shape of the Corvette’s side rocker panel.
A few specialty performance builders, such as Joel Rosen of Baldwin-Motion fame, installed the ‘65 – ‘67 units on his ‘68 and a few ‘69 Phase III Corvettes. While they didn’t fit exactly right, they still looked great. Rosen also added the first generation side-pipes and covers to his Phase III Camaros, Novas, Chevelles, and Biscayne supercars, although due to the short Corvette wheelbase, the system was less aesthetically successful than the C3 Corvette application.
During the 1970s, Hooker Header side pipes on Corvettes were quite common and helped un-cork whatever engine they were put on. This is Craig Cardwell’s 1970 LT-1 and was a LOUD beast!
So aside from the barking exhaust note and added bragging rights, what did the side-pipe exhaust system do for the car’s performance? Unlike the C6 Dual Mode Exhaust system, the old side pipes were never promoted to increase horsepower at all, or at least, they were never officially tested and certified. Of course, the only way to really answer that question would be to rear-wheel horsepower test, say a 427/435 427 ‘67 Corvette with and without the side-mounted exhausts. A lot of work just to find some numbers.
Craig Cardwell bought his 1970 LT-1 new and had the dealer install the side pipes.
So, I took the question to two genuine experts – veteran Corvette racer, Dick Guldstrand and Mike Cederstrom, owner of Sweet Thunder Chambered Exhaust Systems, in Cadillac, Michigan. Since Guldstrand has spent thousands of hours building and racing Corvettes for over 50 years, I thought Goldie might know how much horsepower the side-pipes were worth. Dick’s answer was somewhat surprising. “Those old chambered pipes did improve the engine’s performance, but not much. But then again, almost anything you did was an improvement over the stock system. The ram horn manifolds were pretty good, but nothing like big tube headers with proper phasing and the scavenger effect. But they sure sounded good!”
My conversation with Guldstrand was very historical. According to Mike, GM first started using the low-restriction chambered pipes as part of the ‘61 Oldsmobile Starfire performance package and standard equipment on the ‘64 – ‘65 models. But since the pipes were mounted under the cars and not on the sides, hardly anyone took notice. Meanwhile, over at Chevrolet, with the new big-block 396 engine coming out in ‘65 and the L84 Fuelies were making their last appearance, the Corvette designers wanted a little something extra and got approval to offer the chambered-pipe Off-Road Exhausts optional on all model Corvettes.
The chambered pipes have distinctive “crimps” on the exterior. Inside of each side-pipe is an inner 1-3/4” inner baffle tube with hundreds of small perforations. The crimps on the exterior are there to create the chambered sections, these are specific sizes that combined with the special perforations on the inner baffle tube. These two factors are what they used to help control different exhaust sounds. The “muffling” effect comes from all of those tiny perforations, which burn off after a few years of regular use. With only a 1-3/4” inner baffle tube, you can see why some call the side-pipes “chokers” and why Guldstrand commented that they helped a little, but not much.
The Sweet Thunder Company started making true factory-style, replacement chambered side pipes for Corvettes in the late 1990s. Not the crimps on the outer shell of the side pipes. All the crimps do is hold the inner pipe.
An educated guess might be close to what the new Dual Mode Exhaust System is worth – around 6-horsepower. Had the inner perforated tubes been in the neighborhood of 2-1/2-inches, horsepower increases would have been more substantial. “Why” the 1-3/4-inch inner tubes were chosen is anyone’s guess. Design engineers may have felt that was “enough.” Or perhaps larger diameter inner pipes were experimented with and were determined to be excessively loud. Within my extensive library of Corvette history books, I have never read of an accounting of side-pipe development. It is widely believed that mid-year Corvettes equipped with factory RPO N11 – the “Off-Road Exhaust System” consisting of a pair of GM “Hi-Flow” mufflers in the stock 2-1/2-inch exhaust system would out-perform side-pipes.
See the small perforations? They act like little sound scoops. That’s all that does any kind of muffling. The little perforation burn off after a few years, leaving an owner with an extra loud Corvette! I know, I had one that everyone complained about. “Your car is SO LOUD!”
Of course, side-pipes of one kind or another had been showing up on racing, experimental, and show car Corvettes since earliest Fuelie racers in ‘57 and the stunning Corvette SS racer. Many of Bill Mitchell’s important show and concept cars wore their exhausts on the sides from the ‘59 XP-700 dream car to numerous modified production-based show cars, as well as his Mako Shark I and Manta Ray cars. The Mako Shark I had exposed header pipes protruding from the sides of the fenders that blended into a collector fitted to a decorative, finned muffled cover. While these setups looked dreamy as show cars, exposed header pipes on a production car would never happen. But they did help pave the way for the tamer but deliciously loud chambered side pipes. Until steel tube headers became common, most racing Corvettes used the stock ram horn cast-iron manifolds and would either have a 2-1/2-inch diameter open pipe that exited just in front of the rear wheel or ran along the side rocker. This setup was obviously considered “open” exhaust and was completely illegal for the street.
Not that the factory optional chambered exhaust didn’t create a few problems with young Corvette owners, such as myself. Several inspection officers at my local DMV threatened to not pass my ‘65 Coupe with factory side-pipes because they didn’t like loud cars. I always passed… barely. Once I was told that if I came back next year with THAT CAR, it would DEFINITELY not pass! It wasn’t until my conversation with Sweet Thunder Mike that I learned why my ‘65 Coupe was so loud. Mike asked, “Were those original pipes?” To the best of my knowledge, my car came from the factory that way. They certainly weren’t “header” side-pipes. When I owned the car, it was 10 years old. Mike said, “That’s why. Those little perforations that were stamped into the very thin aluminized steel, didn’t last that long. The whole inner tube would just rot away. You were running nearly straight open exhausts!” he laughed.
I shared with Mike that my girlfriend at the time once said to me, “Your car is really cool, but it’s deafening!” Of course, it didn’t keep her from wanting to drive it from time to time. Once I thundered by a fellow in a 356 Porsche. As we were approaching a traffic light, I could see that he was quite agitated and was yelling at me, “I only got FOUR CYLINDERS, MAN! Four cylinders!!!” I thought, “Well, don’t complain to me!” So I pushed the clutch in and barked the side-pipes for good measure. Another time I passed a coworker friend on the way to work in a, shall we say, ‘spirited fashion” at around 6,000 rpm in second gear. Later in the office, my friend came over to my drawing board and said, “That car of yours is SO FRICK’N LOUD, I could feel the side windows in my Camaro rattling!”
Chambered exhaust systems eventually found their way into Camaro, Chevelle, and dealer-installed AMX cars. Usually, these systems ran under the cars to not draw too much attention. Former VETTE editor and founder Marty Schorr had a tricked out, black 390 Javelin with a set of ‘65-’67 Corvette side-pipes and covers. And what can only be considered a true anomaly was that a small handful of new Corvette buyers opted to have their new Corvettes equipped with dealer-installed Hooker Header side-pipes.
While repro side-pipes have been available for some time now, the guys at Sweet Thunder have invested a lot of time and energy into the reproduction of these new side-pipes with the correct sound. For more information and photos, visit Sweet-Thunder.com. Mike and his team also make chambered exhaust systems for the new 2010 Berger Chevrolet Super Camaros, as well as chambered exhaust systems for several other cars.
So, will side pipes ever come back as a production option for Corvettes? The short answer is, “No!” And many would ask, “Why would anyone want them?” After all, strictly “by the numbers” when offered, side-pipe-equipped Corvettes only accounted for 10-to-11-percent of new Corvettes. However, the side-pipe systems were available for many years through your local Chevrolet Parts Department, to be self-installed by owners. For several decades, ‘75 and newer C3 Corvettes that were equipped with catalytic converters could not have side-pipes and pass inspection. However, now that all of the C3 Corvettes are well over 25 years old and are considered “historic” cars, there’s a lot more leeway.
And what about C4 Corvettes you ask? The folks from Power Effects® obviously have a passion for side-pipes. What’s surprising about their Side Effects® system is that it’s actually a Cat-Back design. The factory catalytic converters remain in place. Just south of the catalytic converter is an aluminum splitter that makes a 90-degree bend to the right and left sides. The splitter is located in alignment with the final exhaust exit. The exhaust weldments bolt to the splitter, then make a 90-degree bend forward and bolt to the sound chamber that captures excess sound. Exhaust gas is then allowed to escape out the exhaust tips in front of the rear wheels.
There is a built-in heat shield attached to the weldment which keeps the composite side panels cool to the touch.
These panels can be painted to match the car’s body color or even custom painted, as seen in our photo sample. The system is available in two sound modes; “Sport” has a deep, throaty tone while “Touring” is a little quieter. Unlike the old factory side-pipes, this system has been dyno tested. L98-powered C4 cars can expect an additional 23-HP while LT1 and LT4 cars can expect a 10-HP gain. For C4 owners, this is an attractive way to personalize your machine. You can review their entire line of performance exhaust systems at PowerEffects.com.
With the introduction of the C5 Corvettes, design parameters were changed to make the new Corvette more of a GT, or Grand Touring machine. Then Corvette chief engineer, Dave Hill, brought his considerable experience working on Cadillacs to the Corvette line. Corvettes had a long history of quality issues and Hill wanted to make sure that owning a new Corvette wouldn’t be a headache. After the C5 was introduced, Hill’s team went on a hunt to eliminate as much excess noise from the cars as they could afford, but at the same time, not lose the car’s performance character. Hill explained that the C5 was the kind of car you could drive for 500 miles and feel good when you arrived at your destination. When he was outlining the parameters for the C6, he determined that after driving 500 miles in a C6 Corvette, the driver would feel GREAT! Obviously, droning side pipes wouldn’t fit into the equation.
The other factor in the demise of side-mounted exhausts was advances in exhaust systems in general. The biggest being the introduction of crossover and H-pipes. Besides emissions, the biggest factor has been noise restrictions on new cars. In order to be certified for production, carmakers must design the cars so that they pass decibel standards in a variety of conditions from various distances. The Corvette’s Dual Mode option is an interesting way to get around those standards because the solenoids only open the flaps during “high load” conditions. You could call the new system, “Bark On-Demand.” Considering that the C6 Corvette is more GT car than ever, the new setup is truly having your cake and eating it too. Well done, C
The Spring 1990 issue of “Corvette Quarterly” was a banner issue for 1963 Corvette Grand Sport fans. Late in 1989 arrangements were made for a very special meeting at Sebring International Raceway, in Sebring, Florida. Two Corvette race cars, separated by twenty-five years gathered for some comparison testing between the Grand Sport #002, known as the “Wintersteen 427 L88” Grand Sport #002 Roadster and the 1989-90 Morrison Engineering and Development Trans-Am Corvette.
On hand to witness and advise was then-retired, former Corvette Chief of Engineering, Zora Arkus-Duntov. In the 1970s GM’s corporate retirement age of 65 mandate was in place, and Duntov was put out to pasture, way too soon in December 1974 when he turned 65. GM president Ed Cole and Sr. VP of Styling, Bill Mitchell faced similar fates at GM. You can read the amazing track comparison of the Grand Sport and the Trans-Am Corvette in Pt. 4 of The Duntov Files.
This story, “Zora Looks Back” offers some interesting insights into Duntov’s tenure at GM, as well as the “Lightweight Grand Sport Corvette” experience. For instance, Duntov said, “It was a quick and dirty sledgehammer project that we put together in a couple of months. There were so many compromises and constraints that we made something of which I am not particularly proud.” Interesting. Well, we sure love them!
Duntov was there, this was his baby, and he would know the real skinny on the Grand Sport. For Grand Sport race car fans, this article by Bill Oursler is a real treat! – Scott
PS – You can access the entire collection of Corvette E-Booklets and the Duntov Files HERE.
Lyn Adam’s 27th and 28th Corvettes; 2015 Z06 & 1964 Wintersteen Grand Sport Corvette Replica
Dateline: 2-24-21 – This story was first published in the April 2018 issue of Vette Vues Magazine –Owning lots of Corvettes is typically something mostly guys do. But Lyn Adams of Litchfield Park, Arizona is no ordinary Corvette lover. Lyn is actually a transplant from Philadelphia, Pennsylvania. In 1967 Lyn’s father bought her a 1966 Ford Mustang convertible, a pretty cool car for a young lady back in the day. But it wasn’t what she really wanted. Lyn wanted a Corvette! She quickly traded in the Mustang at a local Chevy dealer and got what she really wanted; a 1967 327/300 Corvette convertible. That was Corvette 1-of-28!
Lyn truly has an eclectic taste for Corvettes. While her first Vette was bone stock small-block (those 327/300 engines had 380 lb/ft of torque, more than an L84 327 Fuelie!), her affection for Corvettes runs the gamut from mild-to-wild. Many of Lyn’s 28 Corvettes were just drivers, but most were personalized to some degree; some mild, some wild. Except for the Z06 Corvettes, all of her Corvettes have been convertibles.
We’re showing a few of Lyn’s previous Corvettes that include; her 2009 GT1 Championship Special Edition Z06 (number 24 of 38 yellow versions that were built), this is the car she traded in to get her 2015 Z06), a red 2005 Corvette with black & white checker trim, a Millennium Yellow with black & yellow checker stripes and red stripes (this car had a nitrous system that her husband Jody installed), a white 1996 Corvette with black & white checker trim, a red 1976 Corvette with a supercharged 350 and Hooker Header side pipes, and a custom-bodied 1966 Corvette that Lyn’s husband Jody built, packed with a 427 big block with dual quads on a Pro Stock-style tunnel-ram intake manifold, and an L88 cam.
Not shown is Lyn’s first 1967 327/300, a 1966 with a 350 built to a 365 (this car was stolen and then sold), another 1967 Corvette, a 1979 Corvette with Corvette Light Blue paint and a oyster-white interior, a red 1990 Corvette, and another 1967 Corvette painted with the pearl white paint on the “belly of the shark” blended up into purple.
For a period of Lyn’s Corvette ownership experience, she had three Corvettes at a time for 10 years in a row!
Lyn’s current stable of Corvettes (only two) consists of two cars that couldn’t be much more different. The 2015 Z06 was purchased new and is a modern electronic supercar with all the creature comforts one could want. This is a car that if driven with discipline can be a daily driver or a grand touring car.
The 1964 Wintersteen Grand Sport Replica is a throwback to the old mechanical performance cars.
The Grand Sport replica was built by Lou Dussia; owner of Dreamboat Marina in Warren, Pennsylvania. In 1997 Lou found a 1964 Corvette convertible owned by local resident, Charlie McKinsey. The car was under blue tarps and had been sitting in Charlie’s front yard for eight years. The car was complete enough for a project car, so Lou bought it for $5,000.
The car is a “looks-like” tribute car and is based on a production 1964 Corvette convertible, so there’s no tube frame, lightweight suspension components, and all-out racing hardware on the car. However, this is an impressive and stout street rod Corvette, but not a daily driver or anything you’d want to take a long trip in. Lynn and her husband won’t be driving this car to Bowling Green. Let’s look at the details of the 1964 Wintersteen Grand Sport No. 12 replica first.
When Mr. Dussia found the bare bones of this 1964 Corvette in a junkyard in Pennsylvania sometime in the 1990s, it was probably a few years away from total disintegration. The year-round damp climate in Pennsylvania eats old, unprotected cars alive. After Lou disassembled the car, the frame was cleaned, repaired where needed, and most of the suspension parts and drum brakes were replaced and rebuilt to basically stock. The wheel flares, hood, dash, and front and rear panels were manufactured by Wrangler Boats of Akron, Ohio.
The view under the hood is close to period correct and mighty impressive. The 400-cubic-inch small-block Chevy was bored to 406-cubic-inches. The heads are aluminum with a mild 10.0:1 compression and there’s an MSD Ignition. What looks like a set of classic Weber Carbs are actually Dellorto Carbs with short air stacks. This setup might be replaced soon.
There’s no chrome on the engine, as everything is polished. The exhaust headers are ceramic-coated and the side-pipes are fabricated. Lyn is considering replacing the current header/side pipe set up with a set of Hooker Header side pipes. The transmission is a 4-speed Muncie with a Hurst Shifter. Dan Ruhlman, of Dans Auto and Speed in Youngsville, Pennsylvania, performed all of the engine work.
The dash panel of the car imitates the real Grand Sport Roadster racecar. The interior is nicely finished with racecar flavor, trimmed in rich blue carpeting, refinished white door panels, and white OBX Racing Seats. Lyn replaced the factory-original steering wheel with a smaller-diameter steering wheel from Summit Racing for additional legroom between the seats and wheel. Steering effort isn’t a problem thanks to power-assist steering.
She also plans to soon get a convertible top for the car and clear headlight covers so that the car can be driven at night and on not-so-warm Arizona days. Lyn recently added the 18-inch American Racing Heritage Series Wheels, shod with Nitto Tires; 295×35 ZR18 on the rear and 255×35 ZR18 on the front. Tires and wheels were purchased from Big-O Tires, in Surprise, Arizona. These are the style wheels that were typically used on the 289 and 427 Shelby Cobras in the 1960s. Lyn chose them as an “in-your-eye” poke at the Cobras form when the real Grand Sports beat the pants off the Cobras at the Nassau in 1963.
In 2008 builder Lou Dussia needed quick extra cash to help complete a land purchase and sold the car to Mike Terry of Indiana in July of 2016 for $25,000. Terry did not drive the car very much and quickly sold the car. Owner number three added the Wintersteen livery and put the car up for sale. You can tell from just the small sampling of Lyn’s previous Corvettes, she likes her Vettes on the wild side. When Lyn bought the car in November 2017 for $42,000, it only had 390 miles on the new odometer. Typically, street rods don’t rack up a lot of miles.
After taking delivery of the car, Lyn and her husband Jody discovered numerous minor problems, which Jody took care of. As of this writing in the end of January 2018, the odometer now reads 468 miles. Since street rods are almost always “works-in-progress” cars, more changes and upgrades are in store.
Now let’s move on to Lyn’s modern supercar, her 2015 Z06 Corvette. Unlike her 1964 Grand Sport Replica, the C7 Z06 is not only loaded with 650-horsepower and 650-lb/ft of torque, it has creature comforts and goodies never imagined in a 1960s performance car. It is truly a night-and-day comparison! Chevrolet packs so much into the basic Z06, the only real options are; coupe or convertible, manual or automatic transmissions, interior appointments, stripes and trim, and the Z07 Performance Package that takes the car to “track car” level.
Lyn chose Velocity Yellow Tintcoat paint with a black hood stripe, the taller rear wing, and black wheels with thin yellow pinstriping around the edge of the rims. She really wanted the 8-speed manual transmission, but there was an availability issue with Bowling Green, so she took RPO MSU 8-Speed Paddle Shift Automatic Transmission option; which makes the Z06 a few ticks quicker.
Lyn wanted an all-black interior, so she went with the 2LZ Equipment Group that includes; Bose 10-speaker stereo system, cargo net, and shade, head-up display, memory package, auto-dimming inside and outside mirrors, heated and vented seats, power seat bolster/lumbar, advanced theft deterrent, and universal home remote. So far, Lyn added a Jake hood graphic to the black hood strips that are gloss black on one side and matt black on the other one side, and had a clear bra installed that runs from the front to the back of doors.
Lyn Adams and her Corvettes are no strangers to Vette Vues, Her 1966 Corvette with the big-block 427 and tunnel ram was in the January 2002 issue and her 2009 GT1 Championship Edition Z06 was in the December 2013 issue. Her husband, chief mechanic, and best friend Jody says he doesn’t mind cleaning and wrenching on Lyn’s Corvettes, but the Grand Sport will probably get some changes soon. It won’t be long before they’ll start to hit the local car shows, and no doubt, more trophies will be coming home. So what lies ahead for Lyn Adam’s Corvette experience? More Corvettes, I’m sure. – Scott
PS – Since this story was first published in the April 2018 issue of Vette Vues, Lynn’s Grand Sport has been given some sweet upgrades. I will be updating this story soon.
How did Zora Arkus Duntov’s tube-frame 1963 Grand Sport stack up against a 1989 tube-frame Trans-Am Corvette?
Dateline 2.16.21, Story by Paul Van Valkenburgh, Photos by Mark Harmer – To download the free PDF E-book, CLICK HERE – Of all of the five original 1963 Grand Sport Corvettes, GS #002, known today as the “Wintersteen Grand Sport” is the only Grand Sport to have big-block, 427 L88 power. Sports car racing was evolving so fast that by 1965/1966 the Grand Sport was obsolete, despite copious amounts of horsepower and torque. Like all of the Grand Sport Corvettes, after George Wintersteen was done racing the car, it was bought and sold many times.
Today, the car resides at The Simeone Museum, in Philadelphia, Pennsylvania. Occasionally the car is brought out into Simeone’s two-acre courtyard for their monthly Saturday “Demonstration Days”. If you are in the Philly area, check Simeone’s schedule to see when you can see, hear, and smell a classic American beast race car.
Late in 1989 Corvette Quarterly (formerly “Corvette News”) arranged a special event. Grand Sport #002 was brought together at Sebring International Raceway for a side-by-side comparison test with the then “state-of-the-art” tube chassis Trans-Am C4 Corvette. Twenty-six-years separate the two cars, they are both tube-frame cars with replica bodies and powered by Chevrolet engines. But that’s where the similarity ends, and the difference is startling.
The Grand Sport’s lap time was 1.34.22 and the Trans-Am Corvette’s lap time was 1.22.45. Technologies across the board all added up to a much-improved race car. Enjoy the comparison. – Scott
Here are the PDF download links to all 3 of the Duntov Files…
Dateline: 7.31.19 – As seen in the January 2019 issue of Vette magazine, Illustrations by K. Scott Teeters – When the 1963 Sting Ray made its public debut in September 1962, it was a total, “WOW!” And it wasn’t just the Corvette’s stunning new looks; it was the all-new chassis and suspension. By late 1959 Zora Arkus-Duntov was in charge of Corvette engineering. When Bill Mitchell’s design team started work on project XP-720 (the all-new Sting Ray), Duntov was called in to set the parameters for an all-new chassis. The completed Sting Ray looked like the sportscar from another planet and the chassis had everything except four-wheel disc brakes. Today the running chassis looks like a buggy compared to the stout aluminum, steel, and magnesium chassis’ of the C5, C6, and C7 Corvettes. But in 1963 the top-performing L84 Fuelie engine only had 360 “gross” horsepower and 352-LB/FT of torque putting power-to-the-ground with 6.70×15 bias-ply tires. That’s not much twisting on the chassis, so the chassis was more than adequate.
Even when the high-torque big-blocks arrived in 1965, for street use, the Duntov chassis could handle the job. The design didn’t start to show its limitations until the 1968 L88 racing Corvettes with wide tires started competing in long endurance races. Tony DeLorenzo once commented that after long 12 or 24-hour races, their Corvettes needed new frames. Their solution to this problem was a Logghe Brothers full welded-in roll cage. Greenwood’s wide-body Corvettes were so reinforced many asked, “Is there still a Corvette in there?” But for street use and spirited driving, the Duntov chassis served the Corvette well until 1982. Lets look at the chassis’ basics to see why it lasted so long
The genius of Duntov’s chassis was how much lower the center of gravity was. Chevrolet engineer Maurice Olley was a production car chassis and suspension expert when he designed the C1 chassis. As a racing expert, Duntov knew he had to get the center of gravity much lower. The C1’s chassis had a parameter frame with x-bracing in the center for rigidity. The car’s occupants sat on top of the frame. Everything measured from there; the cowl height, engine height, and everything else.
Duntov’s design eliminated the x-brace so that the occupants could be placed down inside the frame, dramatically lowering every data point from there. For rigidity the new frame had five crossmembers. Duntov then mounted the engine and transmission as low and as far back as possible and routed the exhaust pipes through holes in the second frame crossmember. The passenger compartment was pushed back as far as possible and the spare tire was mounted below the back of the frame and under the fuel tank.
The lowering of the engine/transmission and passenger compartment lowered the center-of-gravity from 19.8-inches to 16.5-inches. Moving major components as far back as possible in the shorter 98-inch wheelbase created a front/rear weight distribution of 47/53-percent. The engine centerline was offset 1-inch towards the passenger side because passenger footwell requirements were less than the driver’s. The extra offset reduced the transmission tunnel width and allowed the crankshaft and rear axle pinion to be on the same centerline. Ground clearance was just five-inches.
The build of the frame used boxed longitudinal sides with five crossmembers that were designed to suit the needs of styling. The new frame actually received computer analysis to determine the thickness needed for the parameters of the overall car. The front crossmember was welded to the sides and not bolted-on like the C1 chassis. The new frame with mounting brackets weighed 260-pounds, the same as the C1’s frame, but torsion rigidity increased from 1,587 lb/ft to 2,374 lb/ft per degree.
The C2/C3 suspension was a parts-bin marvel, although it didn’t seem that way. Duntov wanted an independent rear suspension and was immediately told, “No! It’s too expensive.” To get around this, Duntov used almost 60 full-size passenger car front suspension parts, including pressed-steel wishbones and ball-jointed spindles, and just rearranged them. The parts had already been engineered and proven, thus saving production cost. With a 9-degree slope, the wishbones gave an anti-dive reaction upon heavy braking. Then the inner pivot points were lowered to raise the roll-center to 3.25-inches above the ground. A recirculating-ball steering unit was placed behind the suspension and used a hydraulic damper to reduce kickback. All of these changes were very apparent when combined with the right shocks and anti-roll bars when the cars were first driven and tested. The money saved was more than what went into the rear suspension.
The independent rear suspension started with the differential pumpkin bolted to the 4th crossmember with the driveshaft as a device to control forward thrust from the wheels. Axle half-shafts with universal joints are on each side of the differential. Steel box-section control-arms carry the outer half-shafts and attach to the rear frame kickup assembly. Shims at the forward pivot-points are used to adjust toe-in alignment. Strut rods attach to the strut-rod bracket bolted below the differential and connect to the rear spindle support on the control-arms. The nine-leaf transverse spring with polyethylene liners between each leaf to reduce noise, mounts under the differential and is sprung against the rear portion of the control arm with long bolts. Duntov’s proposal to use a transverse leaf spring was not well received by Chevrolet chief engineer, Harry Barr, but no one could come up with a better plan.
For its time, Duntov’s chassis worked very well, but I’m sure that no one imagined it would be used for 20 years. The design proved to be easy to update. Disc brakes were in development when the Sting Ray came out and arrived on the 1965 model. When the new Mark IV became available in 1965 the suspension got stiffer front springs and larger diameter front and rear stabilizer bars. The new chassis was totally adaptable and could be made near-battle-ready with suspension component changes. During the 20-years of Duntov’s chassis, Racer Kits included; the 1963 Z06, 1967-1969 L88, 1970-1972 LT-1 small-block ZR1, and the 1971 big-block ZR-2. And from 1974-1982 there was the FE7 Gymkhana Suspension for spirited street driving. On the street, Duntov’s chassis could easily handle the 327 Fuelie to the LS6 454.
In the ‘70s chassis changes were made to conform to tightening regulations. Starting in 1973 the chassis had to handle the new 5-mph crash bumpers and steel side-door guard beams. In 1975 catalytic converters helped reduce emissions, but cloaked engines. A steel underbelly had to added to the chassis as a heat shield against the very hot converters. 1980 saw a big weight reduction from 3,503-pounds to 3,336-pounds thanks to an aluminum differential, lighter roof panels, thinner material on the hood and doors, and the use of the aluminum L84 intake manifold on the standard engine. The following year, a fiberglass-composite rear leaf spring helped shed 29-pounds. Early ‘80s Corvettes don’t get much respect because their restricted engines, but their drivetrain and suspension was as good as ever. An early ‘80s Corvette with a classic SBC crate engine would make for a stout performer.
Yes, Duntov’s chassis looks crude by today’s standards. But Corvette development is always empirical. If it weren’t for the C2/C3 chassis, there never would have been a C4 chassis, and so it goes. – Scott
Dateline: 2-28-19 – Images: GM Archives; Graphics & by K. Scott Teeters
Of the six men in our “Corvette’s Founding Fathers” series, Peter Brock had the shortest career at GM, but his contribution was enormous. Like all of the Founding Fathers, Brock had “gasoline in his veins” and was cut from the same cloth as Larry Shinoda; post-WW-II southern California, the birthplace of modern hot rodding.
Brock got the car bug at the age of 12 when he spotted a 1949 MG TC with a broken engine in back of the garage where he had his first after-school job. Brock studied the lines and mechanicals of the MG TD and at 15 bought the car. With help from his car pals, he got the car running. Brock’s second car was a 1946 Ford that he made into a fast, award-winning hot rod. Whereas Shinoda’s “Chopsticks Special” hot rods were scrappy-looking drag racers, Brock’s Hot Rod Ford was a sleek beauty that was quick at the drags and had class-wins at the Oakland Roadster Show in 1954 and 1956
.While pit crewing for some older car pals that were racing, Brock decided that he wanted to race, but Brock observed that racing was an expensive enterprise. He determined that he’d better first learn a trade. And since automotive design was his second passion, he’d have to go to Art Center College of Design.
Brock’s approach to getting into the school was stunning; he walked in and told the receptionist that he wanted to attend. The lady asked about his portfolio and Brock had to admit he didn’t know what a portfolio was. After she explained, Brock went to his car, created a series of drawings on blue-lined school paper, came back in after a few hours and said, “Here’s my portfolio.” He made his case that after a month, if his work wasn’t approved, he’d leave.
Brock didn’t see much value in life drawing, light and shadow, and graphics classes. But the “Transportation 101” class was exactly what he was looking for. With great teachers, classmates, and his enthusiasm, Brock was ready for his next big break. His only problem was that he ran out of money! GM Designer Chuck Jordan was then working as a headhunter scouting new talent. When Brock explained his situation to Jordan, he received a round-trip ticket to Detroit for an interview with GM, and later a job offer. Brock later said, “GM was like going to the best grad school. The best education a car designer could hope for.” At 19 Brock was the youngest designer ever hired at GM.
Brock couldn’t have been happier and would often work after hours. One evening Design Director Harley Earl entered the design studio and struck up a conversation with Brock. Earl asked Brock what he thought of GM’s design direction. Surprisingly, Brock told Earl that GM needed to look into the small car market because the Europeans was making inroads and GM needed a small “student’s car” for young people that couldn’t afford a new bigger car. Earl was intrigued. After several more evening conversations with Brock, Earl informed Brock that he was starting the XP-79 Cadet project and that Brock was to lead the design effort, under the direction of a studio boss! What an astonishing opportunity!
Brock went through the entire design process, from sketches, and line drawings, to a full-size mockup that looked like a small European GT. Earl loved the concept and expanded it to include a delivery vehicle. But when Earl showed the $1,000 Cadet concept at Styling’s 1958 line review meeting, there was dead silence. GM president Harlow Curtice said, “We don’t build small cars at GM!” The project was dead, but it did plant a seed that soon became the Corvair.
Harley Earl was about to retire, and his Olds Golden Rocket-like C2 Corvette concept was going nowhere. Around the same time the 1957 AMA Racing Ban killed all racing activity. But 46-year-old Bill Mitchell was about to take over as VP of Design upon Earl’s retirement, and had his own ideas of what the next Corvette should look like. The main Chevrolet design studio was where official GM advanced production designs were created, but Mitchell also set up a special Studio X where he could do his own private design work. After returning from the 1957 Turin Auto Show, Mitchell gave his Studio X team photos of cars that most impressed him; the streamliner record cars from Abarth and Stanguellini, and the Alfa Romeo “Disco Volante” coupe. He liked the bulging fenders and sharp horizontal crease line, and instructed his team to sketch some ideas based on the photos.
A few days later, Mitchell came back to review his team’s progress. He carefully looked at all the drawings and stopped at one and said, “Whose work is this?” Brock raised his hand and Mitchell said, “Nice! I’d like everyone to take a closer look here because this approach to the theme has some real possibilities. Your goal is to expand on this. Let’s see how we can approve.” Studio head Bob Veryzer might have been peeved because he put Brock’s drawing away! But during the next review, Mitchell asked, “Where’s that sketch I approved?” Veryzer put the Brock sketch back up and Mitchell said, “Yes, that’s the one! This is what I want!” That’s how Brock got in the lead design team.
Brock refined his design and explored removable roof panels, unique door hinges, and a roll bar built into the B-pillar. Several weeks into the project, Mitchell asked Brock if he knew anything about Earl and Duntov’s 1957 SS Racer. Brock explained that he and several of his designer friends drove around the clock to Sebring to see the car race. Mitchell was impressed and then explained that he had acquired the SS mule chassis and intended to use it as a successor to Earl’s car, and work on it as an “advanced concept”. Thus the XP-87 was born.
Based on Brock’s refined sketches, a work-order was released for a 1/5th scale model to be built. Because of UAW regulations, all of the clay work would have to be done only by the modelers and Brock couldn’t even touch the model. What Brock learned was that the modelers were outstanding, fast professionals, and totally open to his sugestions; they were there to serve the designers. Once again, Brock was learning from the best.
Around the same time, Ed Colewas pushing his Q-Chevrolet line concept that would have all 1960 Chevrolet cars, including the Corvette, use a transaxle for better weight distribution, and to eliminate the interior transmission hump. Duntov’s engineering layout included an all-aluminum fuel injected engine, a four-speed transaxle, four-wheel independent suspension, a platform chassis, and inboard brakes. A full-size space buck was built and Brock and the team translated the 1/5th scale mode into a full-size clay model. Brock commented that with the space buck, everything fell into place. Unfortunately, the entire Q-Chevrolet concept collapsed due to cost and was diluted down to a less expensive car more suitable for production.
Peter Brock explains the Stingray Racer.
But Mitchell still was hooked on Brock’s design. The XP-87 project morphed into Mitchell’s Stingray Racer and then into the 1963 Corvette project, both driven by the capable skills of co-designers Larry Shinoda, Chuck Pohlmann, Tony Lapine, and Gene Garfinkle. Because of the AMA Racing Ban, Brock saw no opportunity to be involved with anything connected to racing, so he left GM on good terms, and went back to California to begin his racing career.
Post GM Brock raced an ex-Le Mans team Cooper and later upgraded to a Lotus II Series 2, coming in runner-up two seasons in a row to veteran racer Frank Monise. Through providence, Brock was Carroll Shelby’s first employee and set up the Carroll Shelby School of High Performance Driving, ran Shelby’s Goodyear Racing Tire operation, helped develop the very first Shelby Cobra. Brock also created the Cobra Daytona Coupe to take on the Ferrari, won an FIA GT World Championship, and World Speed Records at Bonneville.
In 1965 Brock started Brock Racing Enterprises and raced Hinos, Datsuns, and even a NASCAR Mercury until 1972. After Brock decided to end his racing career, he got into hang gliding. In recent years Brock has worked as an automotive photo journalist and authored a book about the Daytona Cobra Coupes, and “Corvette Sting Ray: Genesis of an American Icon. In 2017 Brock was initiated into the National Corvette Museum’s Hall of Fame in 2017. Brock Brock’s single sketch was the beginning of the Sting Ray. – Scott
Here are the links to the previous five parts of the “Corvette’s Founding Fathers” series…
