presented by

The Revs Institute

1957 CORVETTE SS

1963 CORVETTE GRAND SPORT

John Fitch and Zora Arkus-Duntov

THE REVS INSTITUTE IS PLEASED TO PRESENT AN

HISTORIC EXHIBIT FEATURING TWO OF THE CORVETTES

THAT ESTABLISHED CHEVROLET’S LEGENDARY RACING

REPUTATION. MEETING FOR THE FIRST TIME, BOTH

RACERS FLAUNT THE SHEER EXUBERANCE WHICH

IMMORTALIZED THE CORVETTE’S STANDING AMONG

THE MOST RESPECTED SPORTS CARS ON THE PLANET.

KARL LUDVIGSEN RECALLS THE HISTORY OF

History

A RACING ENTHUSIAST

AND COMPETITIVE DRIVER,

DUNTOV BELIEVED

IN BUILDING SPECIAL

CARS FOR RACING, AS

OPPOSED TO MODIFYING

PRODUCTION CARS.

In July of 1956 a clay model of a sports car on a 90-inch wheelbase—the same as the D-Type Jaguar—took shape in the Chevrolet Studio at Styling, under the direction of Clare MacKichan. Its rounded contours, he recalled, were influenced by those of the D-Type, much-admired among his stylists. One of them was the talented Ron Cadaret, who led work on the racer-to-be.

Created under Styling Staff’s XP-64 designation, by October the racer’s styling development was essentially final. Its teardrop-shaped headrest concealed a strong circular rollover bar while rear wheelhouses were handsomely semi-enclosed. Its final wheelbase was 92 inches with 51.5-inch tracks.

The SS represented the styling of the original 1953 Corvette carried to its most glamorous and indeed sexy extreme. It was the ultimate expression of the Harley Earl Corvette era. A machine of great individuality and character, the XP-64 would be dubbed the Corvette SS, for Super Sport.

Tremendous racing success not only in America but also around the world made Chevrolet’s Corvette one of the most respected sports cars on the planet. This was not the work of a moment. The Corvette’s racing career began near the middle of the last century after a white-haired Russian engineer with a thick accent joined the staff of Chevrolet Engineering. Zora Arkus-Duntov made the Corvette his own project, indeed his whole life.

Although Duntov was a racing enthusiast who had driven in competition, he was a firm believer in building special cars for racing instead of modifying production cars. He believed that this was the best approach for Chevrolet and its Corvette. That’s why Zora was not much involved with Chevy’s spontaneous decision to race stock Corvettes at Sebring in 1956. “I was not the driving force in ‘Let’s Go Racing,’” he said. “I was reluctantly pushed into it.”

Having seen his Corvettes struggle against the fine-tuned racing machinery of the Europeans at Sebring in March of 1956, Chevrolet general manager Ed Cole came around to Zora’s argument that special racing Corvettes were needed. But his preoccupation with other problems in GM’s largest division made Cole hesitate to bless such an initiative. However he green-lighted it after styling chief Harley Earl put him on the spot by threatening to restyle and re-engine a D-Type Jaguar as a Corvette for racing.

In his design of the SS’s chassis Zora Duntov had to dance to Harley Earl’s tune, said stylist Bob Cumberford: “We kept feeding Duntov body drawings and he had to fit everything inside them, rather than us clothing his chassis.” Earl’s dominant position arose from the fact that in an agreement with Chevrolet, Styling Staff was paying for the complete fabrication of the Corvette SS body. This included its skin of exotic magnesium.

Duntov’s Skunk Works

Walled off by curtains and unpainted plywood sheets in a corner of the Chevrolet Engineering Center, Zora Arkus-Duntov created what would become known later as a “skunk works”. With desks and drafting tables next to mockups, trestles and surface plates, Zora worked around the clock with his hand-picked crew toward the almost-impossible goal of designing and building raceworthy cars for Sebring in 1957. Masterful fabrication work in the prototype shops of Chevrolet and Styling followed their drawings.

With time at a premium the designers followed the principle of the 300SL’s multi-tubular steel space frame, adapting it to the SS’s unique design. Suspension was parallel-wishbone in front and de Dion at the rear, the latter thought best for Le Mans—which was Chevrolet’s ultimate goal. Coil springs wrapped around tubular shocks at all four corners. Knowing there was no hope of proving a suitable in-house disc brake in time for Sebring, the Chevy men designed drum brakes for the SS. Mounted inboard at the rear, the brakes had vacuum boosters intended to give an anti-lock effect.

Use of aluminum and magnesium kept the Corvette SS light. With its 450-pound modified V-8, producing 307 bhp at 6,400 rpm with fuel injection, it scaled 1,850 pounds dry, 100 pounds less than Jaguar’s

D-Type. Needing a test vehicle, Zora managed to sneak enough duplicate SS pieces through the GM workshops to make a running automobile out of a chassis that had been described to his management as an “assembly mockup”.

Both the SS and its ugly-looking test “Mule” were taken to Sebring for the 12-hour race on March 23, 1957. Nominated drivers were John Fitch, a Mercedes-Benz team member in 1955 and still a top driver, and Piero Taruffi, a silver-haired Italian racer with engineering skills that would be beneficial to the untried SS. Also piloting the Mule in practice were Briton Stirling Moss and Argentina’s Juan Fangio, reigning world champion. Fangio turned the second-fastest lap of Friday practice at 3:27.2, quicker than the fastest 1956 race lap of 3:29.7. It remained one of the best times set in the 1957 practice session. And the race SS was 150 pounds lighter.

Completely untried, the racing SS revealed two major faults. Its sweeping exhaust manifolds combined with the magnesium body to create oven-like cockpit conditions. Also the vacuum-boosted brakes were locking the wheels unpredictably. “I felt that we had somehow been cheated,” John Fitch recalled, “that if we had only been allowed another month the bugs would have been ironed out of the SS. Now with its malfunctioning brakes and many non-race-tested components I was very much afraid of failure—in fact, it was almost a certainty.”

The SS completed only 23 laps, punctuated by pit stops for flat-spotted tires, coil trouble and failing rear-suspension bushings. Taruffi pronounced the final verdict to Fitch: “To go on is without purpose.” And to Cole: “Withdraw the car.” Although its Mule version became the successful Stingray sports-racer of 1959-60, the SS never raced again. Before being gifted to the Indianapolis Motor Speedway Museum, which has kindly loaned it for this historic exhibit, it lapped GM’s circular track at Phoenix at 183 mph.

“I FELT THAT WE HAD SOMEHOW

BEEN CHEATED, THAT IF WE HAD

ONLY BEEN ALLOWED ANOTHER

MONTH THE BUGS WOULD HAVE

BEEN IRONED OUT OF THE SS.

– JOHN FITCH

The Corvette SS was brought to a screeching halt—to use a favorite Duntov expression—after Sebring by GM’s acquiescence to a spring 1957 agreement among America’s auto makers to cease participation in racing and in the publicizing of racing successes. That ban remained in place in late 1962 when the sensational new Corvette Sting Ray first raced at Riverside in California.

Engine: V8 283cubic inches (4.6 Litre)

Wheelbase: 92 inches Weight: 1,850 lbs.

Corvette SS1957

ENTER THE

Grand Sport Corvette

“THE CAR HAD HANDLING

SUPERIOR TO THE PREVIOUS

MODEL, LOWER DRAG THAN THE

PREVIOUS MODEL. I THOUGHT

THAT THIS CAR WOULD NOT

ONLY SNAP AT GT-TYPE FERRARIS

BUT ALSO TAKE INCREASES

IN POWER, AS SUBSEQUENT

DEVELOPMENT PROVED. I FELT

WE WOULD BE THE VERY TOP

DOG, BETTER THAN FERRARI IN

THIS TYPE OF COMPETITION.

Zora Arkus-Duntov stormed into the 1963 model year with his brand-new Sting Ray, updated from stem to stern. “The car had handling superior to the previous model, lower drag than the previous model,” he said. “I thought that this car would not only snap at GT-type Ferraris but also take increases in power, as subsequent development proved. I felt we would be the very top dog, better than Ferrari in this type of competition. The calculation was made without Carroll Shelby!”

Shelby’s Ford-powered Cobras—husky Ford V-8s in light British AC chassis—seized production-car championships that had been Corvette territory. “Lots of us still felt Corvette should be winning races,” Zora said. Others above and below him in Chevrolet shared that opinion. “Since we can’t build special vehicles and since our production vehicle isn’t capable of competing,” thought Duntov, “maybe we should have a limited production of some lightened version.” This, compelling in its logic and simplicity, was the idea behind the Grand Sport Corvette. Making and selling them could be a profitable enterprise.

Zora’s scheme was only feasible because Ed Cole’s successor as head of Chevrolet, starting in 1962, was Semon

“Bunkie” Knudsen. As a new man in the division, Knudsen had several things going for him—and he knew it. He was not hamstrung by preconceived ideas about what could and could not be done at Chevrolet. His inspired revival of moribund Pontiac gave his superiors confidence in his ideas.

With a minimum of fanfare within the corporation, in the summer of 1962 Chevrolet engineers started working on the car they came to know best as the “Lightweight”. In much the same manner that the SS was built, a secret “skunk works” was created in a windowless workshop off a back corridor of Chevrolet Engineering. Those who backed the “Lightweight” were audacious enough to believe that it could not only beat other GT cars but could also be capable of taking the overall wins that counted for world-championship points.

Founded on the brand-new all-independent suspension of the 1963 Sting Ray, the GT version was a look-alike of the new coupe built to the lightest possible weight consistent with reliability. One hundred and twenty-five of

these Grand Sport Corvettes were to be built and sold to serious racers on a first-come, first-served basis. Duntov and Knudsen were confident that because these cars would be only raced by private teams and owners, not by Chevrolet, they would not contravene GM’s adherence to the industry-wide ban on racing—which, in fact, had been repudiated by both Ford and Chrysler the previous May.

Steering wheel, shifter, basic instrument cluster and windshield wipers were the only standard Corvette parts used in the Grand Sport. Frame members were tubular steel, carrying a fiberglass body made ultra-thin that dropped onto the frame in one piece. Headlamps were fixed behind fairings

Under the aegis of John Mecom, Jr, a wealthy and sports-mad Texan, three GS coupes appeared in Nassau, the Bahamas, for international races on the town’s airport in December 1963. Bulging with wide wheelhouses and perforated with scoops and vents, the Mecom-blue-gray Corvettes exuded automotive testosterone.

Although the Grand Sports were still too underdeveloped to compete over long distances, they showed to advantage at Nassau, far outshining the hated Shelby Cobras with 11-second lap-time advantages. “The whole week was a red-letter week for Chevrolet and a black one for Ford,” Zora Duntov wrote to his superiors after his return. “In the last battle of the season in the war between Chevrolet and Ford, the winner and again champion was Chevrolet.”

GS performance gave a much-needed lift to the spirits of Corvette owners and enthusiasts. For 1964 the coupes were sold to private teams, followed in 1966 by release of the two roadsters. In this special exhibit the Collier Collection’s Grand Sport chassis number 004 is presented with the livery of Delmo Johnson’s entry at Sebring in 1964, co-driven by Dave Morgan. This and its sister GS Corvettes are magnificent machines with an awesome air of forbidding malevolence.

Difference

risk his bonus over a few Corvettes. But Duntov had the makings of five cars that could be raced without the 16-valve engines. Though they would have to race against outright ‘modified’ cars, they might make good showings.

In the hands of dealer Dick Doane and Gulf Oil executive Grady Davis two Grand Sports raced in 1963. Driven by Corvette expert Dick Thompson, the Davis car scored an outright victory at Watkins Glen in August of 1963. Late in the year Chevrolet extensively tested the Grand Sport, making modifications that would not have been allowed in production-car racing such as huge increases in wheel and tire width plus Weber carburetion and intake manifold improvements that allowed the 377-cubic-inch engines to produce 485 bhp without their special cylinder heads. Moreover two of the five cars were completed as roadsters instead of coupes to reduce their aerodynamic drag.

of Plexiglas, used also for all windows except the windshield. Front suspension was similar in geometry but much lighter while rear half-shafts—acting as part of the suspension—were beefed up to take greater torque. Britain’s Girling supplied vacuum-assisted disc brakes.

Corvette’s standard V-8 was the basis of the Grand Sport’s engine, although made of aluminum and expanded to 377 cubic inches from the standard 327. Pushrod-operated valves in new aluminum cylinder heads were vee-inclined in hemispherical combustion chambers with dual ignition. The fuel-injected eight produced 532 bhp at 6,400 rpm with 469 pound-feet of torque at 5,600 rpm. No one had yet built a GT or sports-racing car with so much punch.

Parts for the first five cars were made in the skunk works. Bunkie Knudsen authorized the building of 20 more Grand Sports and 40 of the special 16-plug engines. This would be sufficient materiel for the 1963 racing season. The series of 100 additional cars was scheduled for production at the plant of an outside contractor to Chevrolet. Most were to be trimmed as road cars to ensure a broad base of market acceptance. Public launch was scheduled for January 1964 for the production Grand Sport, which was Corvette Model 887. The follow-on, in the wake of racing success, was to be a run of 1,000 cars.

In January of 1963 this promising and attractive program came “to screeching halt” after both external and internal reassertion of GM’s racing ban by chairman Frederic Donner. Wealthy though he was, Bunkie Knudsen was not going to

The Grand Sport

Engine: V8 377cubic inches (6.2 Litre)

Wheelbase: 98 inches

Weight: 2,150 lbs.

Corvette GS1963

In His Own Words: Karl Ludvigsen “When the Corvette SS was being built, I was the technical editor of Sports Cars Illustrated. My friend John Camden, a free-lance engineer, was drafted in to help build the SS. From my New York office I spoke with John in the “skunk works” about the car under construction. This head start helped us wipe the floor with our rival Road & Track in our coverage of this most spectacular Corvette.”

“In 1963, when the Grand Sport Corvettes were being built, I was a GM public relations man. In this role, Zora Duntov admitted me to the new “skunk works” where the cars were being constructed. It was quite a sight to find how beautifully their components were shaped to save weight from the original design. Zora also loaned me the Shelby Cobra that Chevy had bought for comparison for some laps of familiar Tech Center roads. Exciting stuff!”

ADVANCED RESERVATIONS REQUIRED239-687-REVS (7387) purchase tickets: revsinstitute.org

2500 South Horseshoe Drive Naples, Florida 34104

1957 Corvette SSCourtesy of the Indianapolis Motor Speedway Museum

1963 Corvette Grand SportCourtesy of the Collier Collection

Corvettes photographed by Peter Harholdt