The Corvette division approached Lotus with the idea of developing the world's fastest production car, to be based on the C4 generation Corvette. With input from GM, Lotus designed a new engine to fit in place of the L98 V8 that was powering the standard C4. The result was what GM dubbed the LT5, an aluminum-block V-8 with the same bore centers as the L98, but with four overhead camshafts, 32 valves. Lotus also designed a unique air management system for the engine to provide a wider power band by shutting off 8 of the 16 intake runners and fuel injectors when the engine was at part-throttle, while still giving the ZR1 375 hp (280 kW) when at wide open throttle.
The vehicle went on sale in 1990 and was available only as a coupe. It was distinguishable from other Corvette coupes by its wider tail section, 11" wide rear wheels and its new convex rear fascia with four square shaped taillights and a CHMSL (center high mounted stop lamp) attached to the top of the hatch glass instead of between the taillights.
The ZR1 displayed stunning ability both in terms of acceleration and handling capabilities, but carried with it an astonishingly high price.
In 1991, the ZR1 and base model received updates to body work, interior, and wheels. The rear convex fascia that set the 1990 ZR1 apart from the base model found its way to all models, making the high-priced ZR1 even less distinguishable. Further changes were made in 1992, including extra ZR1 badges on the fenders and the introduction of Acceleration Slip Regulation (ASR) or traction control. For model year 1993, Lotus design modifications were made to the cylinder heads, exhaust system and valve train of the LT5, bringing horsepower up to 405. In addition, a new exhaust gas recirculation system improved emissions control. The model remained nearly unchanged into the 1995 model year, after which the ZR1 was discontinued as the result of waning interest, development of the LS series engines, cost and the coming of the C5 generation. A total of 6,939 ZR1s were manufactured over the six year period. Not until the debut of the C5 platform Z06 would Chevrolet have another production Corvette capable of matching the ZR1's performance.
Although the ZR1 was extremely quick (0-60 mph in 4.4 seconds, and onto 180+ mph), the huge performance of the LT5 engine was matched by its robustness.
Source: Mecum Auctions and Wikipedia, 2011