kenash

Yep! Ditto brother Barnette468....
My ride (s)....

groho

thanks for the feedback, measured specs, and put data into the summit compression calculator and come up with a 9.7CR which is right in line with my objectives. This is not changing anything the rotating assembly, cuz its not necessary since this is a recent rebuild by the PO, bearing/rod and bearing/cap clearances check at .012, and cam bearings look nearly unused. I need to use a hipo head gasket to achieve this CR. Unless I can find better the thinnest I can find is .039 using a 351W head gasket from felpro. I'd like to see a .035-037 if possible, can anyone suggest something? The rearend will remain a 3:25 tracloc, but intend to change to a 3:73 if I can locate a gearvendor O/D. It's much cheaper to drop in a G/V than upgrading the entire tranmission assembly to a built AOD or 5-speed.

kenash

Hi,
Why would you want to tighten the quench that much? Running iron heads together with a tighter quench is going to increase your detonation factor.
Can I ask what are the numbers you used and how did you determine them in arriving at the 9.7 CR?

groho

I won't be running iron heads, I'll be running AFR165, 58CC. the specs were, 3.5" stroke, 4.030 bore, .047 piston to deck clearance, +8cc valve relief pistons, 58cc heads, .039 heads gasket = 9.71:1 CR

kenash

OK, looks like you got the right numbers going on. The reason I thought your were running iron heads was your reference to 351 head gaskets. But, your choice in heads is a good one. I run a similar setup, but, am running a 10.6 CR static. Did you CC the piston reliefs or take what the mfg. stated? The reason I asked, I run Probes and they were not what was listed by them. So, I CC'd all of them. Also know the area between the top of 1st ring and the top of the piston is a couple of CCs. I believe it was 2 CCs in my case. There is a CR calculator that will provide your dynamic CR through the input of the opening and closing events of your cam.
I've since forgotten this, but, there is a minimum "quench" that you will want to maintain. I might have it somewhere in original assembly sheets.
Good Luck....