Edelbrock Heads On 221ci Flathead?

I've recently picked up some used, new Edelbrock heads. The engine in my '36 is a small bore 24 stud, 221ci engine.

As the Edelbrock heads are designed to give a 8:1 comp ration with a 3 3/16" bore is it worth me bolting them on the small bore engine or does the drop in capacity/compression ratio make them worthless on the smaller engine?

I'm already running the stock 81A heads skimmed 60 thou.

Thanks

 

I definitely think it would be worth it. I have a 221 inch '40 Ford flathead with Edelbrock heads on it. The smaller displacement will shrink your compression ratio but not that much. I would guess that the 8.0 ratio would be slightly reduced but it would be at least 7.5 or better. I run a vintage pair with 9.5 stamped on them. The other advantages of these heads will be better heat conduction and a larger water capacity for better cooling. Biggest problem with them is electrolysis - watch your gasket selection and use aluminum compatible antifreeze.

 

Huh...

 

Sorry if that was confusing. Compression ratio is calculated by dividing the volume of the cylinders when the piston is at the bottom by the volume when the piston is at the top. If you increase the displacement of your engine, then you will slightly increase the compression ratio ( volume when the piston is at the bottom is now larger but the volume with the piston at the top remains the same. Aftermarket cylinder heads for the flathead ford had their compression ratios calculated for a stock 239 engine. The 221 engine will therefore have a slightly smaller compression ratio with the same heads. Hope that makes sense.

 

Not confusing. Interested in increase over milled heads. Waiting for all gurus to add in.

 

Thanks Ol' Blue. Good info.

 

Only real way to address this is to get CC info and do the arithmetic...but PM your email and I'll send you a chart that will allow some reasonable guesstimating. Almost all stock 221 heads are pretty large capacity/low compression and improvement by milling is unlikely to approach an aftermarket head like this, as my guesstimate!

 

Nah....total waste of time. Send 'em to me and I will send you my stock ones.