Speedmaster PCE281.1800 Pontiac 389 400 455 215cc 72cc RAM Air Alum Bare Head

Pontiac 389 400 455 215cc 72cc Ram Air Aluminum Bare Cylinder Head Speedmaster Pontiac heads include valve sizes at 2.11" Intake, and 1.66" While the 2.11" valves are standard issue, the valve seat can be machined to accept a larger valve with minimal work. CNC Ported heads in this application will soon be available. Speedmaster CNC ported cylinder heads are machined on dedicated 4-axis and 5-axis CNC machining centers to ensure accuracy and cost effectiveness. On the CNC ported versions, combustion chamber, Exhaust and Intake Ports all fully CNC machined for better flow. CNC combustion chambers offer superior control over flame travel and quench area. CNC Ported heads eliminate human error and variation from port to port. Unsurpassed repeatability from one cylinder head to another that is commonly found in "Hand porting & Polishing" Combustion chambers are exact in volume - so every cylinder has the same compression ratio. Each port is the same cross section - so every cylinder can reach higher true RPM potential. Great throttle response and top-end horsepower Highly efficient ports and state-of-the-art combustion chambers shapes for improved performance throughout the rpm range