08/03/2026
More Corvette Grand Sport history... https://www.facebook.com/permalink.php?story_fbid=pfbid098Q75HTYTfzNTcEdo2ucYLVdAUMYnt9Ut4fNLpah1VR5tGpcy8Vor6FVLB28NLDCl&id=61576718095833
In 1962, Zora Arkus-Duntov started building a car in secret. The Shelby Cobra had arrived, and Duntov knew a British roadster with a Ford V8 was about to humiliate the Corvette in international racing. His solution wasn't to make the Corvette faster. It was to build a completely different car that looked like a Corvette and weighed a thousand pounds less. The XP-87 project, later designated Grand Sport, was a tubular spaceframe chassis wrapped in single-layer fiberglass body panels so thin they flexed when you pushed on them. The standard 1963 Corvette weighed 3,000 pounds. The Grand Sport weighed 1,908. Duntov planned to build 125 cars to satisfy FIA homologation requirements and campaign them at Sebring and Le Mans. He got to five before GM's executives discovered the program and shut it down.
The engine was the most exotic small-block Chevrolet ever built. 377 cubic inches from a bored-and-stroked version of the small-block architecture. All-aluminum block, saving approximately 100 pounds over the standard cast-iron unit. Aluminum cylinder heads with hemispherical combustion chambers and twin spark plugs per cylinder. Four Weber 58mm side-draft carburetors with long intake trumpets. Dry-sump lubrication for sustained high-G cornering. Solid-lifter camshaft with aggressive duration and lift. Forged internals throughout. Output: 550 HP at 6,400 RPM from a naturally aspirated 6.2-liter pushrod V8. TRACO, the legendary racing engine shop in Culver City, California, built some of the aluminum small-blocks and got the complete engine down to 350 pounds. A 550-HP V8 that weighed 350 pounds. In 1963. Duntov had even more ambitious plans: hemispherical heads with port fuel injection for the next evolution. He never got the chance to build them.
GM's corporate racing ban, enacted after the 1957 AMA agreement, should have prevented the Grand Sport from ever existing. Duntov built the cars anyway, hiding the program from GM's executive suite. When the executives discovered what he'd done, they ordered the five cars destroyed. Duntov ignored the order. Instead, the cars were quietly sold to private racing teams, removing GM's direct involvement while keeping the cars alive. The driver roster that raced Grand Sports reads like a motorsport hall of fame: Roger Penske, A.J. Foyt, Jim Hall, Dick Thompson, Dick Guldstrand, and John Mecom. Dick Thompson won the first Grand Sport race at Watkins Glen SCCA on August 24, 1963, in chassis 004. At the 1963 Nassau Speed Weeks, Grand Sports driven by Penske, Foyt, and Thompson battled Cobras and Ferraris despite never having the development time Duntov had planned.
All five Grand Sports survived. Three coupes (chassis 001, 002, 003) and two roadsters (004, 005). Chassis 002 is displayed at the Simeone Automotive Museum in Philadelphia. Chassis 004 has been exhibited at the Petersen Automotive Museum in Los Angeles. Grand Sport values are estimated between $5 million and $10 million, though none have traded publicly in recent years. The surviving aluminum 377 engines are individual museum pieces. The Grand Sport was the car that should have beaten Ferrari at Le Mans. It had the engine. It had the chassis. It had the weight. It had Duntov. What it didn't have was corporate permission. Five cars. 550 HP. 1,908 pounds. Built in secret by the most important engineer in Corvette history, sold to private teams when GM ordered them destroyed, and raced by the greatest drivers in America despite never having the development program they deserved. The Corvette Grand Sport is the most important American race car that never got the chance to prove what it could do.
