Callaway Corvette C4 Sledgehammer
Rives Callaway established Callaway Cars in 1977 long after the muscle car craze wound down when high-horsepower performance machines were just a thing of the past. He specialized in producing turbocharger kits to be installed chiefly on European cars. His knowledge, expertise and the start of the turbo era perfectly lined up, and the company took off (via Road and Track).
To show the real potential of the twin-turbo C4, Callaway produced the legendary Sledgehammer Corvette. It was a highly modified and heavily turbocharged 1988 model with 898 HP. Its top speed was over 250 mph. Only two cars ever left the Callaway factory. Even though it was technically a road-legal vehicle, it was basically a prototype.