BBC 300 CFM CNC Cylinder Heads (pr) O/P Assem.

The BBC 300 CFM CNC Cylinder Heads from Air Flow Research deliver professional-grade performance for serious big-block Chevy engine builders and hot rodders seeking maximum flow efficiency. These heads are engineered for builders who demand CNC-ported precision and measurable horsepower gains without compromise. Whether you're building a street engine, competition platform, or high-performance stroker, these cylinder heads provide the foundation for consistent, repeatable power across your entire RPM range.

AFR's computer numerical control porting ensures every runner, chamber, and port is finished to exacting tolerances, eliminating hand-ported inconsistencies that plague lesser heads. The 300 CFM rating reflects the heads' optimized flow characteristics—a carefully balanced specification that supports aggressive cam profiles and fuel injection systems while maintaining street drivability and reliability. The open-chamber design maximizes combustion efficiency, and the included outlet assembly simplifies installation while maintaining OEM compatibility with standard BBC bolt patterns and gasket surfaces. Cast nodular iron construction provides durability under sustained high-boost conditions and repeated heat cycling.

These heads are ideal for BBC applications ranging from 427 to 496 cubic-inch displacements and pair seamlessly with modern fuel injection, carbureted, or forced-induction setups. Installation on existing big-block Chevy engines is straightforward, as they accept standard rocker arms, pushrods, and valve train components. The 94-pound pair weight reflects their robust iron construction, ensuring thermal stability and longevity. Mechanics and engine builders who prioritize flow efficiency, port quality, and measurable performance will recognize AFR's reputation for delivering results that translate directly to dyno numbers and real-world power delivery.