In 1963, the original Grand Sport Corvettes made their first appearance early in the racing season in the C-Modified Class with an RPO production Z06 race package that utilized the stock L84 327/360hp engine. It also came with special finned-aluminum brakes, a 36-gallon gas tank (later deleted), a four-speed, cast-aluminum wheels (later deleted), a stiffer suspension, and heavier shocks. GM sold several of these cars to proven race teams to see what the car could do. This factory Z06 option demonstrated the potential of the Corvette in competition, but unfortunately two deficiencies in the Z06 option were revealed. The production Corvette was too heavy and the excess weight compounded the ineffective drum brakes on the car.
Chevrolet Engineering had an answer: A series of five Corvette race cars would be built using lighter-weight body materials, four-wheel disc brakes, a four-wheel independent suspension, and a big V-8 to complete the package. These Grand Sport Corvettes were to be designed and built in secret. The Corvette's main competition would be the Shelby Cobras, and, with Zora Arkus-Duntov's guidance, Chevrolet transformed a basic production pleasure vehicle into a competitive race car. As part of the conversion process, the car's "birdcage" was replaced with a tubular chassis, transparent lightweight fiberglass was bonded to the chassis, and stamped-steel wheels replaced the original cast-magnesium units. The steering box and differential were also cast in aluminum to save more weight. After the cars were prepared, Chevrolet submitted a homologation application to the FIA so the cars could be cleared to race.
In December 1962, Duntov took Grand Sport No. 1 to Sebring for testing. Since the 377ci engines were not yet fully developed, the car used a modified L84 327 engine for the tests. The car had some braking problems (eventually, vented rotors were applied to the cars), but due to the car running within seconds of the track record, the trip was deemed a success. Soon, GM brass found out about the Sebring tests and the FIA application was withdrawn, thus following the 1957 AMA anti-racing rules to the letter.
Since GM racing activities were at a standstill, GS No. 3 was loaned to Dick Doane, and GS No. 4 to Grady Davis for SCCA racing events. Their results were mixed, primarily due to a lack of factory support. After many modifications, Davis, with Dr. Dick Thompson, was able to win with GS No. 4 at the Watkins Glen SCCA event in August 1963. Both cars were returned to Chevrolet in October 1963. Then, Grand Sports No. 3, No. 4, and No. 5 were modified to reflect what had been learned over the last year of racing. Vents and slots were installed in the body, and new wider wheels and tires were fitted to the cars. Under the hood, the car carried the special all-aluminum 377ci small-block with 58mm side-draft Weber carburetors. Rumor has it these engines produced in excess of 485 hp at 6,000 rpm. Plenty of power, to say the least.
In December 1963, three of the Grand Sport Coupes (Nos, 003, 004, and 005) were shipped to Nassau, Bahamas, for the annual Speed Week. The two Grand Sports that were entered in the Tourist Trophy race on Sunday qualified well-Second and Third on the grid-but both dropped out during the race with overheated differentials. A "vacationing" GM engineer, who just happened to be carrying some in his luggage, later provided differential coolers. They were fitted to the three coupes in time for the Governor's Cup race on Friday. With the new diff coolers in place, the Grand Sports responded well. In Friday's race, the Grand Sports finished Third, Fourth, and Sixth, well ahead of the Cobras. Two Grand Sports entered the final race of the week, Sunday's Nassau Trophy, and finished Fourth and Eighth, again leaving the Shelbys far behind. When the crew returned to the States, the engineers worked to solve the remaining problems uncovered in the Nassau Speed Week events. Air-pressure buildup in the engine compartment of the Grand Sports had required the hoods to be taped down to prevent their exodus. This underhood pressure, combined with the large frontal area and high profile of the coupe body, also created the tendency for the cars to lift the front end at speed. In preparation for the Daytona endurance race in February 1964, the GM engineers converted Grand Sport coupes 001 and 002 to roadsters by removing the roofs to reduce their profile and frontal area. Special louvered hoods were also fitted to relieve the engine-compartment pressure problem.
Unfortunately, these modifications proved to be the last applied to the Grand Sports by Chevrolet Engineering. The Nassau successes and the publicity surrounding the affair again brought the Grand Sport project to the attention of General Motors' corporate brass. As in the past, the brass disclaimed any corporate involvement in racing and ordered the cars destroyed. Insiders at Chevrolet immediately whisked the three coupes off to private hands, where they had modest racing success in later years. The two roadsters remained hidden in Warren, Michigan, for years, but they occasionally surfaced for rare car-show appearances before being sold to Penske in early 1966. All five original Grand Sports still exist to this day in private hands.
Fast forward 30 years: In 1996, the new C5 Corvette was waiting in the wings, ready to change the way many of us feel about the Corvette from that point forward. The last couple of years of C4 production totals continued to slip, as the '97 model year grew closer and closer. Many people in the GM "decision loop" were worried the upcoming C5 could hurt the remaining C4 sales effort.
In 1996, Chevrolet released two new models to try to boost the last model year of the C4, and the Corvette Collector Edition was one of those new models. It was offered in either coupe or convertible and carried a retail price of $1,250. For that, you basically got a special coat of Sebring Silver paint, a leather interior (black, red, or grey only) with the Collector Edition logo embroidered on the headrests, and the five-spoke special rims. A total of 5,412 Collector Edition cars were eventually built.