Mercury was selected to manufacture the LT-5 engine at its MerCruiser facility in Stillwater, Oklahoma, in part because so few engines would be built that General Motors (which owns Chevrolet, builders of the Corvette car) could not manufacture it efficiently, while MerCruiser could offer a very high level of quality manufacturing. In fact, the MerCruiser-built engine was awarded the automaker’s most demanding quality certification — GP3 Level
1.Designed for General Motors by Lotus Engineering, the LT-5 was an all-aluminum 5.7-liter small-block V8 featuring 32-valve dual-overhead-cam heads that generated 375hp. For the 1993 model-year engine, horsepower was bumped to 405 with cam-timing and engine-porting changes. The LT-5 became the most celebrated Corvette engine of its time, accumulating records along the way. In 1991, a slightly modified ZR-1 with a “bone stock” LT-5 broke three world endurance records at the Firestone test track in Fort Stockton, Texas. A team of drivers headed by Tommy Morrison broke the 24-hour endurance mark by almost 15 mph, traveling 4,221.26 miles at an average speed of 175.885 mph. Two years later, a MerCruiser-branded ZR-1 took the checkered flag in the 24-hour World Challenge race in Mosport, Canada, with another ZR-1 finishing second. Production of the LT-5 ended in 1994.