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.
LS based GM small-block engine
The LZ1 is almost entirely based on its predecessor, the LFA, but with some revisions, such as including up-integrated electronic throttle control, long-life spark plugs, GM’s Oil Life System, Active Fuel Management and variable valve timing. It has the same compression ratio, power and torque ratings as its predecessor, the "LFA".
This family of blocks is just an updated version of its Generation III predecessor with Generation IV updates and capabilities. Applications of this family were mainly for trucks but did see some mild usage (with some modifications) in front-wheel-drive cars.