I've always relied on being told "buy this, buy that" from my builder, this one I'm going alone. I just ordered my Trickflow TrackHeat heads TFS-51400010. They have a 61cc combustion chamber. The motor is a '90 302HO, so I figured 4" bore, 3" stroke, my Cometic head gasket is .040 compressed. I didn't know what to figure in for the valve reliefs in the stock HO pistons or the piston to deck clearance. The CR I came up with is 9.5:1

How did I do?

 

Are you planning to measure your block deck height prior to buttoning engine up?

Should verify your actual compression ratio w/ measurements to determine if heads need milling and if gasket selection is ok.

 

do some research on dynamic compression vs static compression. Dynamic compression is much more important. Depending on what camshaft you are running they can bleed off pressure at the bottom end, decreasing the actual compression ratio (Dynamic compression)

 

I'm interested in my dynamic compression on my 351w.

Static compression is 9:1.

I run 93 octane but think I could run lower.

 

Thanks for the info. I was most concerned about too high of a cr just for fuel reasons.

 

I think the factory E7 heads are about 63-64ccs so you will be just slightly higher than stock compression..It will be fine..

 

Sounds like the right ballpark. I'm at 60cc chambers, flat tops .006 below deck with 5cc reliefs and a .047 compressed gasket thickness, puts me at about 9.25:1 static. Custom cam so I'm not worried about dynamic compression, I know it's good