BBC 265cc CNC Alum Heads Magnum O/P

The BBC 265cc CNC Alum Heads Magnum O/P cylinder head from Air Flow Research is purpose-built for high-performance Big Block Chevy engines requiring maximum airflow and reliable street performance. Designed for enthusiasts and professional engine builders who demand precision-engineered components, this assembled aluminum cylinder head pair delivers the flow characteristics necessary for sustained power generation in magnum street applications. Whether you're rebuilding a classic muscle car, upgrading a truck platform, or constructing a high-output performance engine, these heads provide the foundation for efficient combustion and responsive throttle response.

Manufactured using CNC precision machining, the BBC 265cc heads feature a 265 cc intake port volume with a 112 cc combustion chamber—a geometry optimized for balanced velocity and cylinder charging efficiency across the RPM band. The design incorporates 2.190-inch intake and 1.880-inch exhaust valves seated in aluminum construction, paired with 1.550-inch valve springs rated for reliable street-duty operation without excessive wear. Each head arrives fully assembled and ready for installation, eliminating the need for secondary machine work and reducing build time. The aluminum construction provides superior thermal conductivity compared to iron, enhancing heat dissipation and enabling consistent ignition timing under sustained load.

These cylinder heads are sold as a pair and are exclusively compatible with Big Block Chevy platforms, fitting both traditional and modern engine configurations used in street rods, vintage muscle cars, and contemporary performance trucks. Installation requires standard engine block preparation and gasket sealing protocols; professional machine shop verification of deck surface and bolt hole alignment is recommended before final installation. The 265cc port size makes these heads particularly effective for naturally aspirated engines in the 454 to 496 cubic inch displacement range, where port velocity and chamber efficiency directly correlate to throttle response and cruising power delivery.