The fourth-generation Corvette had a huge impact on the marque's performance legacy. Many versions were produced from 1984 to 1996, but two standouts were the ZR-1 and the Grand Sport. ZR-1s were offered as coupes from 1990 through 1995, while Grand Sports were available in 1996 in coupe and convertible form.
The National Corvette Museum paid tribute to both this year at its annual C4 Gathering in Bowling Green, Kentucky. Many rare and unusual ZR-1s and Grand Sports were on display during the event, and many of the key people who were involved in the design of both models were also present. They provided behind-the-scenes stories about the development of these landmark Corvettes during their informative museum seminars.
The C4 was unveiled to the motoring press in the fall of 1983 and soon after was named the Motor Trend Car of the Year. The new design was a complete departure from the previous Corvette, and sales soared. The car relied on modern electronics, vastly improved aerodynamics, and high-tech suspension components to provide owners with exceptional handling and fuel mileage. However, its anemic, 205hp Cross Fire Injection engine was a disappointing artifact of a bygone era. Things improved in 1985 with the introduction of the 230hp Tuned Port Injection (TPI) L98. Over 200 production improvements were built into the '85 Corvette, and these mitigated many of the quality complaints that plagued the '84 models.
The '85 Corvette proved to be the car to beat in showroom-stock sports-car racing. The factory provided heavy support to several teams like Baker Racing and Morrison Motorsports. The results were astounding: Corvettes were unbeaten in every race they entered during the '85 season. However, the car still needed an engine capable of fully utilizing its excellent chassis and suspension.
Work secretly began on an ultra-high-performance variant-known internally as the "King of the Hill"-in late 1985. The Morrison and Baker teams were very involved in the development of this car, which would come to be known as the ZR-1. Many of the heavy-duty parts they used on their showroom-stock race cars were actually tested for the ZR-1 program.
Bowling Green began building prototypes in 1987, and these were used to help develop the new supercar. Production was scheduled for 1989, but a variety of technical issues moved the introduction back to the '90 model year. Eighty-four pre-production ZR1s were built and ended up being used as test cars. One of these prototypes, EX 5669, was used by Morrison Motorsports to break Ab Jenkins' 24-hour average-speed record of 161.180 mph set in 1940. The team handily exceeded the half-century-old mark in April of 1990 with a speed of 175.885. This car is on permanent display at the NCM, and many of the people involved with its record run were on hand at this year's C4 Gathering to celebrate the 20th anniversary of their achievement.
When development on the ZR-1 was completed, many of the prototypes were destroyed. However, some were tucked away by GM and were recently sold at auctions. A few have been located, salvaged, and restored, and now reside in the hands of Corvette collectors. Some of these special pieces of Corvette history were also on display at the gathering. They included two of Tommy Morrison's original Mobil 1 ZR-1 race cars, which were driven to numerous victories during the 1994 and 1995 racing seasons. They're currently owned by collector Robert Pfeffer. Former drivers John Heinricy and Jim Minneker, along with team owner Morrison, were also on hand and were obviously thrilled to see them displayed.
The other C4 to receive special recognition at the event was the '96 Grand Sport. Heinricy, who served as GM's director of High Performance Vehicle Operations for a number of years, provided some background on the car's development during a presentation at the Grand Sport Registry business meeting. Heinricy was serving as Corvette Assistant Chief Engineer in the mid-'90s, and his role was to finish production of the C4, while his boss, Chief Engineer Dave Hill, worked on introducing the new C5. Heinricy, who had been a diehard racer for years and enjoyed many victories behind the wheel of the C4, felt the best way to celebrate the car's 12-year model run was to pay tribute to its performance heritage. He received approval to build a limited-edition model called the Grand Sport, a name that honored the five special Grand Sport Corvettes Zora Arkus-Duntov built for competition in 1963.