Ford Flatheads feature the original Edelbrock script logo design for Fords and Mercurys, and are casted at the Edelbrock Foundry in the USA of T-6 tempered A356 aluminum. These heads are rugged, ribbed internally and externally, with a large water capacity and excellent breathing characteristics. The 65cc heads support 8.0:1 compression ratio on blocks with a 3/16 base relief (stock bore and stroke), compression ratio increase is approximately 3/10 of a percent with each 1/8 stroke. High Lift/Large Chamber versions feature a new raised roof combustion chamber design that is CNC machined for high lift cams and is perfect for reducing compression in supercharger applications or on low octane fuel. High Lift heads have increased valve clearance and increased flow capacity. Match these heads with our popular Ford Flathead Intake Manifolds.