Legendary American Sports Car Corvette Grand Sport

May 5, 2011 - PRLog -- The Grand Sport Corvette created its first appearanceearly in the 1963 season within the C-Modified class with a production 360 HP 327 Fl engine in its lightened 2000 pound body. It raced the season as a "stock" appearing racer. The season finale was held at Nassau each and every year having a "no holds barred" week of races on the island where all of the teams could compete against every other making use of all of the most recent high tech performance parts that were otherwise banned from standard club racing.

When the Grand Sport Corvette made its appearance at Nassau, it looked as if it had been given a big injection of steroids. Flared fenders, hood scoops, wider wheels and tires, as well as other visible adjustments only touched the surface of the technological advances that had been in these Grand Sports

Under the hood of the Grand Sport Corvette was found an all aluminum 377 cubic inch little block with 58 mm side draft Weber carbs. These aluminum engines were of the second casting batch from Chevrolet's Study and Development department.


There were 12 of these aluminum castings made.They were identified by the single letter "A'through "L" which was stamped on the standard location on the passenger side of the engine block. This engine utilized in the Grand Sport Corvette is letter "F" in the series.

These all aluminum engines had been shared with Jim Hall's Chaparral, but his sports racers utilised smaller 48mm webers that had been more suited to the RPM requirements of the distinctive automatic transmissions that were in these revolutionary racing cars.

The Grand Sport Corvettes either annihilated the competition or won every little thing in sight that week at Nassau. The teams were so confident with their wins, that preparation began for the 1964 12 hours of Sebring.

All three Grand Sport Corvettes entered the 1964 12 Hours of Sebring.

Roger Penske and Jim Hall shared a newly painted white Grand Sport Corvette. This car was one of the most prepared car of the group. A pneumatic system was installed on the car which happened to be one of the earliest applications of an air driven jack device on any sports racer. This pneumatic jack system not only reduced pit stop times but also eliminated any damage to the fragile fiberglass body and tube frame that could so quickly happen when changing tires.


The external fittings for the air jacks are seen on the proper front fender of the Grand Sport Corvette. The attention to detail paid off, for this Grand Sport Corvette finished 1st in its class! The '64 season ended with the Nassau races as soon as once again.


Roger Penske returned with his white Grand Sport Corvette for what was to be his final week as a expert driver. Despite the fact that the all aluminum engine performed properly throughout the season, it was replaced with a 364 cubic inch iron block for its final hurrah at Nassau.

The aluminum heads were retained as well as the webers. The iron block was chosen because it flexed much less at high RPM, thus allowing the engine to create a lot more horsepower. The extra horsepower could be needed against the other "no holds barred" racers.

The Grand Sport Corvette was further lightened by removing the pneumatic jack program which brought it's weight down to 1900 pounds! Although the lead in the race was initially held by a lightweight Cobra that was powered by a new 390 cubic inch all aluminum Ford engine, Roger was able to wear down that Cobra, pass it for the lead, and ultimately get the checkered flag.

Roger took nearly a year off from racing after acquiring a Chevrolet dealership early in 1965, but he would return, this time as a team owner. Late in '65 he received a phone call from Zora Duntov, telling him that a racing version of the newly introduced 427 cubic inchMark IV huge block engine would be accessible to select people. It was to be referred to as the L-88. Zora promised that he would take care of the homologation papers and Roger soon took delivery of the 1st production L-88 Corvette. Roger also acquired the last two Grand Sport Corvettes from Duntov shortly right after that. They had been converted to convertibles as a test to lessen lift and wind drag at high speed. It was Rogers concept to install the new L-88 into these drag decreased Grand Sport roadsters and race them one more time at the 12 Hours of Sebring 1966.

One Grand Sport Corvette was picked, the L-88 was installed, the pneumatic jack system which was utilised two years earlier, was installed,and bigger wheels and tires were installed. Roger felt that this setup would be sufficient to maintain up with the 7 liter Ford Mark II GT40's.

Due to the limited preparation time and no testing time, only estimates could be made in regards to tire size and spring rates. The aluminum heads on the L-88 had been replaced with cast iron versions for the actual race ONLY since these iron heads could possibly be ported a lot more aggressively than the new aluminum heads, thus creating more horsepower. In the course of the '66 Sebring, this Grand Sport Corvette did compete competitively with the GT40's but it failed to finish after it was forced off the track by a slower car.

After the race at Sebring, the other Grand Sport Corvette was passed to a friend of Roger Penske,George Wintersteen. George was able to fine tune the Grand Sport roadster with the appropriate springs and tires. The aluminum headed L-88 performed really properly also.

Source : http://www.dreamroad.us/legendary-american-sports-car-cor...

Regrettably, the Grand Sport Corvette was now without having a doubt outclassed by the rapidly evolving Lolas and McLarens that it was forced to compete against. Had the Grand Sport been accessible in this final form back in 1964, it could have possibly even beaten these mid engine prototypes. The owners of today's Corvettes can thank the individuals involved with the Grand Sport Corvettes for the technologies that they now take for granted. Wide tires, wonderful suspension geometry, all aluminum engines, etc. can all be traced back to 1963, when the Grand Sport underwent it's metamorphosis into a muscular sports racer.