Corvette Chronicles: A Look At The 1963 Grand Sport Corvette

When the Grand Sport Corvette first began its storied trek through history, hardly anyone had ever heard of a Grand Sport. In all honesty, even Zora Arkus-Duntov didn’t use the term to describe the cars his team hoped would dominate the world’s racing circuits.

General Motors entered into the Automobile Manufacturer Association’s (AMA) racing ban, which was a knee-jerk reaction to a horrible crash during the 1955 Le Mans race. The Mercedes, driven by French-driver Pierre Bouillin (who raced under the name Pierre Levegh), crashed and went into the grandstands, killing 83 spectators and injuring 180 others. It is considered the most catastrophic crash in automobile racing.

John Fitch, at the wheel of the Chevrolet Corvette Special during the 12-Hours of Sebring, March 24, 1956. (Photo: Registry of Corvette Race Cars/Facebook)

The crash was so catastrophic, Mercedes-Benz pulled out of racing for more than three decades. Pierre’s co-driver in the Mercedes was none other than Corvette superstar, John Fitch. Mr. Fitch continued to participate in racing and made it his life’s work to improve automotive safety — both on and off the track. In 1955, he was picked by Ed Cole, Chevrolet’s chief engineer, to head up the new Corvette Racing team for the following two years.

The Corvette that John Fitch wielded around the twisting Sebring course also competed for speed earlier on the sands of Daytona Beach wearing a high wing and air diffusers over the headlights. The (Photo: General Motors LLC)

Corvette’s assault on the competition under John’s direction in 1957 is legendary. After setting a new class land-speed record on the sands of Daytona, Corvette Racing continued to turn the racing world on its ear as the team struggled its way to the front of the pack during the grueling 12-Hours of Sebring race. The world was put on notice, and no one knew that more than Chevrolet’s racer-gone-engineer, Zora Duntov.

Built For Speed

With the new body style introduced in 1963, Corvette also introduced the high-performance (even for Corvette) Z06. The purpose of the car was unmistakable. It was introduced with a 360 horsepower, 327 cubic-inch engine, Positraction rear differential, heavy-duty suspension, heavy-duty power brakes behind cast-aluminum knock-off wheels, and an oversized fuel tank that holds 36-gallons.

The Corvette Z06 was designed for racing but was based on the production car. It was a 1/2-ton heavier than the lightweight Grand Sport. Note the ’63-only rear split window. Zora notoriously argued against this styling cue, stating that it hindered the driver’s rearward view. Interestingly, his race-only lightweights did not have this feature. (Photo: GM Archives)

Early in 1962, amid the AMA ban, Zora convinced then-head of Chevrolet, Bunkie Knudsen, that Corvette needed to be competitive against Ford’s Shelby-devised Cobras and the best way to do that, was to build special, lightweight Corvettes specifically for this goal. Mr. Knudsen agreed, and Zora’s team started a fresh-slate design of the newly-designed Corvette. The difference is this one would be race-specific, and built to dominate.

Losing weight was the primary concern, and the car’s design focused on achieving this goal by utilizing an entirely new, lightweight body and chassis. Initially powered by the same 360 horsepower, fuel-injected V8 as the Z06, the body and chassis mods carried the car across the scales at around 1,000 pounds lighter.

Intending to build 125 cars to meet homologation rules, only five cars were built before GM’s Chairman, Frederic Donner, found out about the program. He immediately ordered the lightweight Corvette racing program dismantled. From that point, you could say the front door to the lightweight Corvette racing program was welded shut. But, the back door’s hinges were well oiled. Even still, Zora was notorious for getting things done and having someone within GM pay for it, whether they knew it or not.

As far as I’m concerned, if any driver ever says that he had complete control of that car, he’s a liar. – Delmo Johnson, Grand Sport driver

Two cars were delivered to race-team owners, Illinois Chevy-dealer, Dick Doane, and Gulf Oil research-executive Grady Davis. They quickly began confounding the competition in their somewhat-stock-appearing lightweight Corvettes. Zora continued to gather information about his secret solution to Shelby’s Cobras, and late in 1963, the cars were recalled back to Zora’s stables of speed for updating, in preparation for Nassau Speed Week that year.

As soon as they were unloaded off of the cargo ship, the lightweight cars hit the sandy, Nassau ground running. Many outside the halls of Chevrolet knew it would be bringing something special. A few insiders didn't have a clue. (Photo: General Motors LLC)

When the cars hit the docks of Nassau, a crowd surrounded them in anticipation. It was now quite obvious these cars were not factory production models, and even Carroll Shelby stopped by to gather some intel about this perceived competition.

The cars now sported a more aggressive hood, wider front and rear fenders, wider Goodyear tires, and Halibrand wheels. There were also additional cooling ducts for the brakes. The biggest factor of note in the new design was the lightweight 377 cubic-inch, all-aluminum small-block that reportedly made 555 horsepower. A full house of Weber carburetors on a cross-ram style intake replaced the previous fuel injection.

Fast And Fiesty!

Chevrolet’s commitment to dominance was evident in the lineup of drivers for its newest creation. Renowned hot-shoes Augie Pabst, Roger Penske, Dick Thompson, and Jim Hall would take on the world. The cars’ potential — and Achilles’ heel — became evident during its stay on the little island off the Florida coast. Jim Hall summed up his time behind the wheel. “That car was damn fast,” recalls Hall. “But, the rearend wasn’t any good in the car that I drove, and it didn’t last very long in the only race that I drove it in at Nassau.”

All of the lightweight cars succumbed to overheating differentials. Coincidentally, a vacationing Chevrolet engineer just happened to have some differential coolers in his luggage. Between races at the Nassau event, modifications were added, including coolers to help keep the rear differentials from overheating. During races, various issues plagued the factory lightweight Corvettes, but one thing was certain, the cars were wildly fast.

In preparation for the Nassau event, the cars had the recently-completed, 377-cubic inch, all-aluminum small-block engines added. Webers replaced the fuel-injection units used on the previous engines. This 377 engine is on display in the Revs Institute, in Naples, Florida, along with Chassis #0004. (Photo: Registry of Corvette Race Cars/Facebook)

Delmo Johnson is quoted in David Friedman’s Corvette Thunder: 50 Years of Corvette Racing 1953-2003, saying, “As far as I’m concerned, if any driver ever says that he had complete control of that car, he’s a liar.” You can check out this video of Grand Sport chassis number 004 at speed during the 2013 Rolex Monterey Motorsports Reunion and make your own conclusions.

Fame can be a blessing and a curse. While the rigors of racing were sorting out the weak points on Zora’s lightweight Corvettes, the cars still placed better than the Cobras, which was the main reason for their existence. Once the cars were back on native soil, everyone’s eyes focused on the upcoming events at Sebring, Daytona, and Le Mans. Everyone except the folks on GM’s 14th floor, where Frederic Donner spent most of his time.

Perhaps it was the publicity from the cars’ visit to Nassau, or maybe Zora’s internal memo sent out on December 16, 1963, that put the non-factory Corvettes under the hot lights of corporate GM. In his memo, Zora praised the lightweight Corvette’s performance against the Shelby Cobras during the Nassau event. He went on to say, “Since the news of Corvette participating was known to Ford four or more weeks in advance…”

Imagine finding out the project you ordered dismantled was recently competing in full force, in front of everyone. And, the competition across town knew about it for a month or more! A perfect example of, “Think before you hit the ‘Send’ button!”

After Nassau — and Bunkie Knudsen’s long walk up to the 14th floor — the cars were turned over to privateers such as Delmo Johnson, John Mecom, and Jim Hall. Zora originally envisioned building more than 100 of the lightweight Corvettes. He would only provide five: three coupes and two roadsters. He had the roof of cars number 001 and 002 removed, and a small windscreen installed thinking the lower profile would benefit the cars on tracks such as Daytona.

The cars continued to compete through the 1966 and ’67 seasons but were becoming less technologically advanced, as more modern chassis and power systems were implemented. The final race for a Grand Sport was the 1967 Daytona 24-Hour race at the hands of Jim White, Tony Denman, and Bob Brown. The car ran against Ford GTs and Ferraris in the prototype class, since it was never homologated, and had a hard time competing with this class of race car.

The colorful history surrounding the 1963 Grand Sport Corvettes — both inside and outside of GM — is part of what makes them so attractive to enthusiasts and valuable to Corvette historians. All of the cars are now prized items in collections, and their value encompasses more zeros than most calculators can fathom.

1963 Corvette Grand Sport coupe at Sebring. (Photo: Chevrolet)

Interestingly, while Zora risked the ire of the suits within the corporation where he gathered his livelihood, his thoughts after the fact hint that it was all in a day’s work. In Jerry Burton’s book, Zora Arkus-Duntov: The Legend Behind Corvette, he quotes Zora’s statements about the Grand Sport program as, “a quick-and-dirty sledgehammer project, of which I am not particularly proud.”

Perhaps it’s Zora’s European upbringing by which he feels the factory lightweight program didn’t have the proper polish to be considered significant. For everyone else, it’s the Grand Sport’s brash, hard-hitting persona, and the way it bucks conforming to dictates, which resonate so well with the American psyche.

We made tea in the Boston harbor, we put footprints on the moon, and we built a hand-full of stupid-fast race cars that dominated the competition at a time when GM wasn’t even interested in doing anything that involved racing. If there was ever a subtle, single-finger salute from those who get things done to those who don’t see the value, the 1963 Grand Sport project would easily suffice. The fact that it comes to you in a package that is 1,000 pounds lighter than the factory offering is just icing on the cake.

About the author

Andy Bolig

Andy has been intrigued by mechanical things all of his life and enjoys tinkering with cars of all makes and ages. Finding value in style points, he can appreciate cars of all power and performance levels. Andy is an avid railfan and gets his “high” by flying radio-controlled model airplanes when time permits. He keeps his feet firmly grounded by working on his two street rods and his supercharged C4 Corvette. Whether planes, trains, motorcycles, or automobiles, Andy has immersed himself in a world driven by internal combustion.
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