i've got a .060" over 350 and used the federal mogul H345NP,.060 that i got from jegs and the newer catalogs don't have all the info but i went to federal mogul .com and used their calculator and with 64 cc it came out to 10.8-1 if your heads haven't been cut which isn't likely.i'd say about 11.4-1.with premium mine ran fine though.i did only alow .010" deck height and stock should be .020"-.030" and that may change it to around 11.2
This is a procedure that has to be performed with the engine on a stand with no heads attached and a clean precrushed used gasket ONLY NEED TO DO ONE CYLINDER
Using a 100 cc burret to measure volume with water, bring a piston to TDC (I use a dial indicator to be 100% sure). Install a layer of saran wrap large enough to cover cylinder completely,now place the head gasket down followed by the head( make sure valves are installed)
Install all the head bolts and torque to 25 lbs in the proper pattern. Now tilt the engine so that the sparkplug hole is straight up and fill the chamber until the fluid just touches the sparkplug threads. This will tell you how many cc's you really have. Now take that number to our Knowledge Base and do the math
(720.74072+ _____ (the total # in cc's)
_______ (the total # in cc's = compression ratio
If you add up your compression ratio, make sure you know all the details, if your pistons are the common "rebuilder" pistons, they`ll have .020 off the tops. I`m running a .040 350 with 345 speed pro pistons, and these have .020 off the tops, which don`t help compression any. with a compression gauge mine came in at a low 145 psi. when I was using a trw forged flat top of the same design with the same heads it came in at 165 to 170 psi.