airflow · FF-0160

What do porting and relieving do for a Flathead block?

Steve defines porting as slightly enlarging the ports, cleaning up the bowl area and smoothing the casting so air and fuel meet fewer obstacles. Relieving the block between the valves and the cylinder can add about 15 percent flow. He says the block holds close to 30 inches of exhaust port, one reason Flatheads run warm, and recommends mild porting and a relief on any rebuild.

Expert

Steve Coppock

Evidence

expert attributed

Component

intake ports, exhaust ports, and valve relief

Applicable scope

Performance Ford Flathead V8 build as described by Steve Coppock