Which company assembled the C4 ZR1's LT5 engine?

Mercury Marine assembled the C4 ZR-1’s LT5 engine. The engine was designed with Lotus Engineering involvement, but its production and assembly took place at Mercury Marine’s facility in Stillwater, Oklahoma.

The LT5 was an unusual Corvette powerplant: an all-aluminum 5.7-liter V8 with dual overhead camshafts and four valves per cylinder. Those features sharply distinguished it from Chevrolet’s conventional pushrod small-block engines. The engine was developed for the ZR-1, Chevrolet’s high-performance C4 variant introduced for the 1990 model year.

Lotus is a common wrong answer because Lotus Engineering designed the LT5’s advanced cylinder-head and valvetrain concept and helped engineer the engine. Cosworth is also associated with high-performance engine work, but it did not assemble the production LT5. Katech became well known for later Corvette performance development, not for assembling the original ZR-1 engine.

The ZR-1 remained in the C4 range through the 1995 model year. Its specialized engine helped make the ZR-1 a technological flagship rather than simply a more powerful trim package.