Chevrolet small-block engine
In 1992, GM created a new-generation small-block engine called the "LT1 350", not to be confused with the high-output Generation I LT-1 of the 1970s. It displaced , and was a 2-valve pushrod design. The LT1 used a reverse-flow cooling system which cooled the cylinder heads first, maintaining lower combustion chamber temperatures and allowing the engine to run at a higher compression than its immediate predecessors.
Chevrolet big-block engine
The Vortec 7400 L21 was a commercial version of the Chevrolet Big-Block engine used in the medium duty truck platform. Its design shared much with the L29 454, but with the addition of forged pistons and crankshaft, and coil near plug ignition. It had slightly reduced power compared to the L29 454 and used a different PCM. The L21 was paired with the early 4 speed Allison automatic transmission or manual transmission, depending on the application.