BBC 305cc Alm Cylinder Heads (Pair) Assembled

The AIR FLOW RESEARCH BBC 305cc Aluminum Cylinder Heads (Pair) Assembled represent a premium choice for Big Block Chevy engine builders and enthusiasts seeking measurable flow improvement and reliable performance. These assembled heads arrive ready for installation, eliminating the labor and uncertainty of sourcing individual components, and deliver the intake and combustion chamber geometry engineered for horsepower gains across the RPM band.

Each head features a 305cc intake port volume optimized for volumetric efficiency, paired with a 117cc combustion chamber tuned for effective flame travel and burn rate. The 2.250-inch intake and 1.880-inch exhaust valves are sized to balance flow capacity with seat velocity, critical factors in street and strip applications where torque response matters as much as peak power. Angle-plug configuration improves spark plug centering in the combustion chamber, supporting consistent ignition timing and cleaner combustion. The 1.625-inch valve springs provide adequate clamp load for aggressive cam profiles while maintaining reliability under sustained boost or nitrous oxide use. Constructed from aluminum, these heads offer a weight savings advantage over cast iron while maintaining thermal stability.

This assembly is built for engine builders, performance shops, and experienced enthusiasts rebuilding Big Block Chevy platforms for street performance, bracket racing, or power adder applications. The pre-assembled configuration accelerates build timelines and ensures consistent port matching and valve setup from the factory. Buyers integrating these heads into larger builds should verify carburetor jetting, ignition timing, and camshaft duration compatibility to realize full potential.

AIR FLOW RESEARCH (AFR) cylinder heads have held a strong position in the performance engine market for their flow bench testing transparency and real-world dyno validation. These 305cc heads complement a wide range of Big Block Chevy builds, from mild street engines to competition platforms, provided supporting components—induction, ignition, and fuel delivery—are properly matched to the heads' flow characteristics.