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The story of this Chevrolet begins with Fords - specifically, the purpose-built IMSA Mustangs and SCCA Trans Am Mercury Capris that became major forces in those series in 1984-85. In 1985, a Mustang built by Jack Roush and chassis firm Protofab took a young John Jones to the IMSA GTO crown and a Roush Protofab Mercury Capri had done the same in the Trans Am championship.
A Corvette in name only, the Corvette GTP (Grand Touring Prototype) was one of the fastest and most exotic race cars ever to wear a red Bowtie. Based on an English Lola T600 chassis and powered by an all-American turbocharged Chevy V6, the mid-engined racer was a rocketship. At full boost, the Corvette GTP's 3.4-liter (209ci) V6 pumped out more than 1,000 horsepower.
1988 Corvette Challenge Car Series
The 1988 Corvette Challenge Series was created by John Powell of Powell Motorsports. Chevrolet built fifty-six identical Corvettes for the first year of the Corvette Challenge in 1988. Each was equipped exactly the same, with all standard equipment, the 245hp Cross-Fire fuel injection engine, Doug Nash 4+3 transmission, Z51 Handling Suspension package.
While not exactly a "collector's edition" Corvette in its own right, it nonetheless has become a uniquely identifiable and collectible Corvette from the fourth-generation era. 1988 marked the 35th anniversary for Corvette, and so it was decided that Chevrolet should commemorate the milestone by introducing an anniversary-edition model. This anniversary car was the first of its kind in a decade, given that Chevrolet opted not to manufacture a Corvette in 1983.
This is no ordinary C4 coupe, but a GM Engineering test mule with VIN plate EX4607 proudly displayed in the windscreen, built in 1986 to test all the new-for-1988 features. This actual car must have spent weeks pounding round the General Motors Proving Ground at Milford, Michigan with longer runs on the road, testing all the changes for a year which saw the C4 suspension, steering and brakes vastly improved.
When Dick Guldstrand introduced the GS80 series in 1986, the car was targeted specifically at Pro-Solo and autocross enthusiasts. He knew all about the needs of these groups, as he was a longtime provider of performance upgrades for the C3 and a direct supporter of a small team of racers from the Western Council of Corvette Clubs. Up to this point, Dick had basically been a tuner. With the intro of the GS80 he was venturing into the realm of small-volume manufacturing.
Offered from 1987 to 1991, the RPO-B2K upgrade was available from any Chevrolet dealer and also Callaway’s first major Corvette tuning program. Together, GM and Callaway made the upgrade package a Regular Production Order (RPO) which was the first time GM had outsourced such an option to a specialist manufacturer. It even had a factory back warranty. As the C4 updated, so did Callway’s program and by 1988, the B2K was pushing 382 bhp and 562 ft. lbs. of torque.
This Sledgehammer reached 254.76 mph at the Transportation Research Center (TRC) in Ohio and became the world’s fastest street-legal car for some time. It was built up by Reeves Callaway in Connecticut as an example of what was possible with the new ZR1 and and turbocharging its LT5 engine. The result was a 898 bhp coupe that still retained luxuries such as air conditioning and a radio. It got this power by using a NASCAR-spec block with Mahle pistons and a massive turbo.