FLORIDA

What compression will result with 58cc heads & flat top pistons on a 327?

Matt Gruber

if it had 64 cc heads,
then it will go up about 1/2 point

Jebbysan

Scroll half way down and read this chart:


http://www.northernautoparts.com/Pro...tModelId=15094

I would not bother.....the 64/68 chamber flows so much better....especially when the chamber is relieved around the Intake Valve. The Tight chamber shrouds the valve.....and if I remember correctly has tiny Intake vales in it for the 283.

Jebby

MikeM

The '62-'64 250/327 used a 59.6 cc head. I think the advertised compression ratio was 10.25-1. That head used 1.7"/1.50" valves.

If you have the standard cam, those heads will be okay on a 327 up to about 4800 rpm. After that......................

Jebbysan

Good info....I always wondered what made a 250 horse a 250...now i know....it had 283 heads on it!

Jebby

MikeM

Yes,now that you know, know this. In 1965, Chevy put the big chamber, big valve, big port heads you recommended on the same 250 hp engine, and they still rated it at 250 hp with the same compression ratio! And I think at the same rpm.

Jebbysan

That must be the one with the infamous .390 lift cam in it....

Jebby

MikeM

Dunno, I just tried to answer the OP's question.

FLORIDA

I was considering buying a pair of used aluminum aftermarket heads, 58cc chamber with 1.50 exh, 1.94 intake. Just needed to check the effect of the smaller chamber. The chart referenced was useful for compression. Thanks.