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. 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. The A engine formed the conceptual design basis of its successor, the LA engine.