factory modification · FF-0097

Why did Ford add a factory relief between the valves and cylinder on some Flathead blocks?

Steve says Ford's factory relief slightly reduced compression to help control detonation in trucks and may also have reduced cracking stress between the exhaust-valve area and the cylinder. It was not primarily a performance airflow modification.

Expert

Steve Coppock

Evidence

expert attributed

Component

block relief, exhaust-valve-seat area, and cylinder

Applicable scope

factory-relieved Ford Flathead V8 blocks