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.
Short block
A short block is an engine sub-assembly comprising the portion of the cylinder block below the head gasket but above the oil pan. An in-block cam engine includes the camshaft, timing gear, and any balance shafts. Overhead cam engines don't include those parts.