BBC 325cc Iron Cylinder Head 118cc Assembled

The Chevrolet Performance BBC 325cc Iron Cylinder Head 118cc Assembled (Part #12562920) is a purpose-built cylinder head engineered for big block Chevy engine builders seeking maximum intake flow and combustion chamber efficiency. This iron casting delivers the flow characteristics and durability required for street performance, racing, and high-output engine applications where reliability under sustained load is non-negotiable.

Specified with 2.180-inch intake valves and 1.880-inch exhaust valves, this head maximizes breathing efficiency across the RPM band. The 325cc intake port volume is optimized for big block applications, providing the flow required for naturally aspirated or moderately boosted engines. The 118cc combustion chamber contributes to efficient flame travel and helps manage detonation margins. Spring pocket features 1.470-inch valve springs, a proven dimension for street and moderate racing duty. Iron construction provides superior heat dissipation and durability compared to aluminum alternatives, making it ideal for engines experiencing sustained high temperatures or frequent load cycling.

This assembled unit targets engine builders and performance enthusiasts constructing or rebuilding big block Chevy powerplants for trucks, hot rods, marine applications, and track vehicles. Pre-assembly eliminates valve lapping and initial setup, reducing build time while maintaining factory precision. Weighing 77.45 lbs, the head integrates into standard big block Chevy platforms without modification.

Big block Chevy cylinder head specifications have remained a foundation of performance engine building for decades. The 325cc/118cc combination balances peak horsepower potential with streetable characteristics, making it a benchmark reference for entry-level and intermediate builds.