Chrysler A engine
The Chrysler A engine is a small-block V8 gasoline engine built by Chrysler with polyspherical combustion chambers. It was produced from 1956 until 1967, when it was replaced by the wedge-head LA engine. It is not related to the hemispherical-head Hemi engine of the same era.
LS based GM small-block engine
Several versions of the LS were used in the Chevrolet Corvette, beginning with the LS1 in 1997 through the LS9 and others in 2013. Variants of the LT version of the GM small-block have been used since. 
The GM Generation I and Generation II (LT) engine families are both derived from the longstanding Chevrolet small block V8. The Generation III small-block V8 was a "clean sheet" design, which replaced the Gen I and Gen II engine families in 2003 and 1996 respectively.