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
Applications:
"Note 1: depending upon vehicle application; horsepower, torque, and fuel requirements will vary. vin code indicating engine RPO may also not be consistent between vehicle types (cars or trucks) or years. with few exceptions, RPM redline is generally 6000 or higher"
"Note 2: block features are generally dependent upon the Generation but not always built-in. typical features are AFM (Advanced Fuel Management), VVT (Variable Valve Train), Front Wheel Drive (FWD) and other improvements. features marked with an * indicate that only certain model years have that feature"
In the early production run of the LS-series engine, some engines encountered 'piston slap' during the first few minutes after a cold engine start; this sound is caused by the pistons rocking slightly in the cylinder until they reach operating temperature/size. 'Piston slap' sometimes sounds more like a knock or the sound of a diesel engine running. It is typically only present when the engine is cold and disappears as the engine reaches operating temperature. The noise of 'piston slap' often is louder when listening for it below the oil pan.