I have read on here and other websites on how to figure cr but i dont know all of the info like stroke length. Does anyone have an educated guess on what the cr would be on a 350 goodwrench, 76cc and 8.5/1, with 64cc and 58cc heads?

 

the stroke is 3.48". Youstill need more info to calculate the cr. need piston to deck clearance @TDC and piston valve relief volume ( CC) and head gasket volume (CC)

A approx calc..... if the 350 is 8.5:1 now with 76cc heads and you just change the cylinder heads to 64cc
the cr will now be 9.6:1 and with 58cc heads 10.25:1

Most replacement head gaskets are thicker (.039") than the factory (.015") shim gasket with more volume. Have to keep every thing else the same or the cr will not be accurate.

 

here is a good website address to use for calculating. it's exact!
http://www.rbracing-rsr.com/compstaticcalc.html
hope this helps.