• 4-Bolt Billet Steel Main Caps (All are Cross Bolted)
• 2.25" Mains (Use Ford 302 Main Bearings)
• Ductile Iron Cylinder Sleeves w/ 4.120" Rough Bore
• Siamese Bore Casting

Note: These racing engines must be used with a dry sump oiling system, and the gear drive systems shown below.

The Mopar Performance A4 line of aluminum engine blocks & components is engineered for serious performance enthusiasts who demand high strength, lightweight design, and precision. Whether you’re building a high-revving racecar or upgrading your street ride, this series delivers impressive gains in reliability and performance without unnecessary bulk.

One of the key advantages in this line is weight savings. Making the switch from traditional iron blocks to an aluminium engine block dramatically reduces front-end mass, improving handling, acceleration, and balance. These A4 blocks are built with steel billet main caps and ductile iron sleeves to maintain strength where it counts, even under the stress of aggressive camshafts and high cylinder pressures.

If you’re putting together a four-cylinder setup, these blocks give you impressive flexibility. The engine block 4 cylinder versions are well suited for classes where displacement and weight matter, offering high RPM capability and reliable performance without the compromises of heavier materials.

Builders looking for precision and durability will appreciate the heavy deck heights, reinforced girth around the bore, and proven design components in the A4 family. The 4 cylinder engine block options are designed to be fully race-ready with built-in compatibility for the P5, W9, or W9RP head patterns, depending on your goals.

In short, Mopar's A4 aluminum race blocks answer the call for high output, lightweight builds. If you want improved throttle response, better power-to-weight, and a foundation that supports serious performance upgrades, this is your path forward. Add to cart today to lock in the foundation your engine deserves.