The Chrysler A engine is a small-block V8 automobile engine from Chrysler Corporation. It was produced from 1956 until 1967, when it was replaced by the wedge-head LA engine. The A engine's combustion chambers are polyspherical, and it is not related to Chrysler's Hemi engines of the same era.The A engine was first released in 1956, and was used exclusively in Plymouths until 1958. The cylinder bore center distance is 4.46 in (113.3 mm), larger than the earlier Dodge-based poly engines.