Speedmaster PCE281.2033 320cc 119cc Hyd Roller Assy Cyl Heads for Chevy BBC

Chevy BBC 454 320cc 119cc Hydraulic Roller Assembled Cylinder Heads Assembly Specifications Max Lift: .580 Coil Bind: .740 Intake Install: 145lbs @ 1.9 Exhaust Install: 145lbs @ 1.9 Closed Sear Pressure: 145lbs Open Seat Pressure: 360lbs As with all Speedmaster cylinder heads, our Big Block Chevrolet heads are Gravity Die Cast . This casting process creates a much more uniform and robust cylinder head. With the increasingly large displacements becoming common, the need for more airflow is necessary. If you are looking to build a 400-500+hp engine, give our PCE281.1489 heads a try. They offer a smaller cross - section to increase the incoming air s velocity, resulting in great driveability, power and economy. On engines over 500hp, use the rectangle port PCE281.1488 heads. The mid-size cross section works well on engines under 540cu.in and under 7000RPM. If you are working on a larger, or higher RPM engine, step up to the CNC ported PCE281.1511 heads. The added volume of the PCE281. Assembled with the finest premium components to provide your engine with optimal airflow for maximum engine performance Improved power throughout the rpm range for greater throttle response and top-end horsepower