hi all ,could some plz clarify these pistons plz.. i have a 327 and mine are identical to the ones in the picture,they are a dome of approx 4mm high..i have 462 ,64cc heads and am trying to find a compression figure..

 

You'd have to provide piston to deck clearance measurement and compressed thickness of the headgaskets you plan to use. The part # of the pistons would also help to look up the cc's displaced by the piston.

 

Estimating dome cc from a picture is pretty dicey. I'll guess you're somewhere around a + 6-10cc net dome volume looking at those.

Like was said above, without actual specs you can be way off. When you get up into the higher compression ratios it only takes a handfull of cc's to make the difference between 11:1 and 12:1!

 

hey i understand where ure coming from ,.i was wondering how much i can reduce the compression with gasket ,or the worst case senario ive got to swap pistons which wil be a pain in ones posterea!!! heads are 64cc 462 block is standard 327 no machining /deck work..

 

I'm taking a wild stab in the dark plugging in specs here, but if you use a real thick gasket like the GMPP .051" composite head gasket the LOWEST I can get it is still in the low 10s for compression. I'm assuming a 4.00" bore, 3.25" stroke, .025" piston deck height, +6cc of piston dome and 64cc heads along with 11cc for the thick GMPP .051" head gasket to come out at 10.0:1 compression.

For comparison sake, I ran some numbers for typical 4 eyebrow flattop pistons (-6cc piston volume) using a thinner .028" GMPP composite head gasket, all else held equal, and got 9.2:1 (with much better quench distance). Same same but with an evn thinner steel shim head gasket and you're at 9.5:1 with optimal quench distance.

 

hey thx for doing that ,,its really helped ..ive no idea wot cam is in this engine ...pistons are 11.25and my heads are cc d at 64cc could u advise a good camshaft. would like a lumpy idle to pull 2700lb ****** pikup 30inch rear tyre 3.70 rear gear ,2500 stall street/strip ,thks again .. was thinking of ex274 /shneider 260h what do u think ??