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.
Chevrolet small-block engine
The Vortec 5700 L31 (Vin code 8th digit "R") is a V8 truck engine. Displacement is 5.7 L. It is the last production Generation I small-block from Chevrolet. The cylinder heads feature combustion chambers and intake ports very similar to those of the LT1 V8, but without the reverse-flow cooling. As such, the L31 head is compatible with all older small-blocks, and is a very popular upgrade. It offers the performance of more expensive heads, at a much lower cost. It does, however, require a specific intake manifold (A 5.7L, 350 CI L31, Vortec engine has eight bolts attaching the intake manifold or four per head, as opposed to the "traditional" six bolts per head; twelve in total found on older Chevrolet small blocks). The L31 was replaced by the 5.3 L LM7. The 2002 model year was the final year for the L31 5.7 L small block V8 whose origins date back to 1955. The Vortec 5700 produces to at 4600 rpm and to of torque at 2800 rpm. It is currently being produced as a crate engine for marine applications and automotive hobbyists as the 'RamJet 350' with minor modifications. Known as the GEN 1+, this was the final incarnation of the 1955-vintage small block, ending production in 2005 with the last vehicle being a Kodiak/Topkick HD truck. Volvo Penta and Mercury Marine still produces the L31. The "MARINE" intake is a potential upgrade for L31 trucks despite its cast iron construction. Using this "MARINE" intake will allow the use of common types of Bosch-style injectors with various flow rates while still maintaining emission compliance.