Corvette Racing Heritage Part 1
Before I get too far into the history of Corvette's in the competition world I want to talk about Zora Arkus Duntov. He has been called the father of the Corvette where in reality, that is a misnomer. He is really the father of the performance side of the Corvette and although if it were not for the performance maybe the Corvette would have never lasted all these years, but the true father of the Corvette has to be Harley Earl, for without him I would not be writing this and you would not be reading it and most likely none of us would be driving a Corvette. With that said let's get started in to the history of Corvette's as it pertains to racing.
The Corvette has been racing almost as long as it has been around. It was 1956 when the first real Corvette race car was unveiled. Prior to this the only notable Corvette raced or shall we say in competition was in 1955 when Zora Duntov took a pre-production 1956 Chevy with the new 265 cubic inch V8 and raced up Pikes Peak setting a stock car record. The only issue here is that it was an unofficial record. That is because there was no sanctioning body. It was not until the United States Auto Club was formed that these types of record runs were recorded. Again Zora not satisfied, he took a Corvette to Daytona Beach the same year and hit a record setting 150 mph over the flying mile.
In 1956, Ed Cole decided the Corvette may not survive without something happening to help promote sales. He thought that this could be accomplished by promoting the car as a performance car that was able to be raced in a production classes. Back in the mid-fifties there were two very important sports car events held each year. They were truly international events. The first in the famous 24 hours of LeMans and the second is the 12 hours of Sebring. Zora knew that a good showing at Sebring was all that was needed for people to realize that the Corvette was in fact a true sports car. The plan was to take this Corvettes to Daytona Beach for top end speed trials. After those time trial the next event would be the famous 12 hour race at Sebring. Hopefully after the Sebring race it would then be sent to France for the world renown 24 hours of LeMans. After all was said and done, a record at Daytona was set, and this new Corvette racer captured the class win and also a decent finish at Sebring. Well this proved Ed was right on target as sales for the Corvette increased and that probably saved the Corvette.
Although Chevrolet was just realizing that the Corvette could be a good race car in the true sports car ranks a dentist by the name of Dr, Richard Thompson, started to get involved in sports car racing in the SCCA (Sports Car Club of America). He race in the Class C Production and had help from of Zora. He ended the year as the champion in the C-Production. 1957 came along and because of his over all performance in 1956, the SCCA moved him up in class to B-Production, which he went out and won that class championship. His secret weapon was a camshaft designed by Duntov. This later became known simply as the Duntov cam.
Also in 1956 Zora began working on the idea of a specialty built race car. Not a stock production car souped up. Out of this came the XP-64 or what would be later known as the Corvette SS. This car although it was not a production Corvette that the general public could purchase it was still Corvette thanks to some styling from the Corvette team. It had the wide smile with a tooth type grill, and the side coves. It also sported a new 283 that would be in the 57 model year Corvette. Designed originally to race at the 24 hours of LeMans, it never saw that goal, but it did appear at the 12 hours of Sebring, but was forced to retire with suspension issue shortly after the race began.
In 1958 and '59 there was a Corvette raced that was known as the Purple People Eater, actually there were three of these cars built. The Corvette was built by a group of people at Nickey Chevrolet in Chicago. This Corvette dominated the B-Production class and in 1959 it won every race it was entered in with one exception and that was the last race of the year.
In 1960 Corvette made its first trip across the pond to France to compete in the 24 hours of LeMans they were all painted white with blue accent stripes and numbers. The cars were number 1, 2 and 3. The number 3 car finished the grueling 24 hour race in first place in the large displacement category.
In 1961 Dr Dick Thompson drove a 1961 Corvette in SCCA B-Production and won that class title. This car was also raced at the 12 Hours of Sebring placing first in Grand Touring 3000 class there and driven by Delmo Johnson and Dave Morgan .
In 1962 the executive vice president for Gulf Oil purchased the Corvette from Yenko Chevrolet. The car was driven by Dr, Dick Thompson. The car was in the A-Production class and in the 14 races that it was entered in it took first place in 12 of those races. Two of the twelve race wins were at Daytona and Sebring. Needless to say it won the A-Production Championship in 1962. The car was sold at the end of the '62 season but was campaigned with success in 1963 under the new ownership. In the race at Daytona it finished second in it class.
Next up is the Grand Sport. In 1962 Zora under tight security started on the planning and development of a purposely built race car to go to Sebring and LeMans. These were not just designed race cars to go to these two important races, but there were designed to go there and win. These cars were to be extremely light weight and powered by a 377 cubic inch small block with Weber side-draft carburetors. The output was rated at 550 horsepower.
Saving weight was a main concern seeing that the production Corvette weight in at 3100 pounds. To get the weight down, the production cars frame was reproduced in light weight aluminum and the body panels were a single layer of hand laid fiberglass that was bonded to the birdcage frame. Cast magnesium wheels replaced the heavy steel stamped wheels of the production car.
Duntov took GS #001 to Sebring in late '62. The Grand Sport was powered by a modified 327 fuel injected engine because the new 377 cubic inch engine designed for these cars was not completed at the time of testing. Even without the 377 the car ran within a few seconds of the Sebring track record.
When the news reached the chairman of GM news came down that all racing activity was to be stopped and the original project to produce 125 Grand Sports never materialized. The reason for this decision from GM management was due to a 1957 Automobile Manufacturers Association ban on direct involvement in auto racing. There were a few of these cars that slipped out the back doors however. Grand Sport #003 and #004 were leant out to profession sports car racers. Seeing that both cars resembled factory production cars and did not have the 377 power plants no one even noticed them. They were only raced for the one year and then returned to the factory.
With the debut of the all new Sting Ray Corvette in 1963, came a special performance option called the Z06. This was a true race car that could be order directly from the factory. It was equipped with larger brakes, vents backing plates, larger finned brake drums, cooling fans in the drums and self adjusting brakes that adjusted the brakes while moving forward as compared to the standard self adjusting brakes that only adjusted while going backwards. The suspension was beefed up with a heavy duty rear 9 leaf spring over the stock 7 leaf version, heavy duty front springs and specially calibrated shocks on all four corners. A 36 gallon fuel tank as added. This car only came with the 360 horsepower fuel injected engine and four-speed transmission with a posi-traction rear end. After all this was a race car not a street cruiser. This was a very limited car with only 199 produced.
In 1966, the first factory 427 L-88 engine and the competition race package was authorized by the Chevrolet Central Office. This C.O.P.O. (Central Office Production Order) Corvette to be built with the J-56 brakes, 36 gallon fuel tank, F-41 suspension, prototype 2:73 positraction rear axle, transistor ignition, M-22 transmission, off road exhaust, radio and heater delete, teakwood steering wheel, telescopic column and a special prototype cowl induction hood. Roger Penske who had worked in Chevrolet's race program was the recipient. Penske wanted the car for the 24 hour Endurance Race at Daytona.
With 1967 came the L88 that was now available to the general public. These cars came stripped of all luxury items. The radio, heater, air conditioning and choke were removed. Chevrolet want to keep the L88 as an all out race car and by deleting these items the hope was that the public would not want them, but to be on the safe side the L88 was rated at 430 horsepower while the L71 was listed at 435 horsepower and was cheaper. In reality the L88 was capable of around 600 hp. The L88 racer for Sebring was the Sunray DX. It came with the M22 four-speed transmission known to many as the rock crusher. Large disc brakes. Aluminum heads and upgraded suspension.
The 1968 L88 Corvette Scuderian Filipinetti was smuggled out the back door to get around the GM ban on racing. The car was raced at the famed 24 Hours of LeMans and driven by Henri Greder and Umberto Maglioli. The big block Corvette dominated the Porsche's and lead the GT class, until it developed engine problems and was forced to drop out after 6 hours.
In 1969 this Corvette returned to LeMans where again it dominated again and lead the GT class for the first 16 hours before again it was forced to retire with mechanical issues. This L88 Corvette was then sold and campaigned four more times at LeMans Mans from 1970-73, finishing as high as 18th overall and 2nd in class. The L88 Scuderia Filipinetti LeMans Racer holds the record at LeMans for single chassis starts (six).
There were other notable C3 Corvette's that carried the Corvette banner. In early February 1968 Don Yenko of Yanko Chevrolet showed up at the 24-hour Daytona race. with a three car team of Sunray DX Corvettes. They were all painted in the Sunray colors of blue and white with red stripes. This was also the debut of the new 1968 Corvette body style, and the team was equipped with two of these new roadsters with hardtops, as well as the 1967 coupe from the previous season. The '67 L88 finished first in GT class and 10th overall. Yenko driving one of the "68 L88's finished 4th in the GT class and 25th overall while the third team car finished 5th in the GT class and 27th overall.