supercharging · FF-0460

What compression ratio should a Flathead built for a supercharger have?

Steve calls it a depends question, but for a supercharged Flathead he targets 7.5 to 8 to 1. That lets him add 7 to 8 pounds of boost on top, keep it on pump gas and still make 290 or so horsepower. He says with better forethought he would have put different pistons in this engine to start closer to 8 to 1; it probably could then have run similar boost, about six pounds, and still been safe on pump gas.

Expert

Steve Coppock

Evidence

expert attributed

Component

compression ratio

Applicable scope

Steve Coppock's supercharged ARDUN overhead valve Flathead, 8BA block, about 289 cubic inches, with a Weiand 177 on the engine dyno at Klein Engines