hey guys, I've got a 402 that needs a new cam, but I don't know what the CR is. I was told it was 9 or 9.5:1 years ago, but not sure and want to get at least a educated guess before I select a cam.

Heres what I know.
open chamber ovals, 2.06 intake valve, unsure of CCs
stock 396/350hp cam
I believe stock pistons, not sure
120psi compression (cold)

can I figure out the CR from this info? thanks.

do a search .There is alot of talk about that here

Here's calculators but you'll still need to know the head cc's(get the casting number) and which pistons(not so easy).
http://cochise.uia.net/pkelley2/index.html
http://www.kb-silvolite.com/calc.php?action=comp
http://www.wallaceracing.com/Calculators.htm
http://www.smokemup.com/auto_math/index.php

Here's another that I use.

http://www.campbellenterprises.com/Race%20math%20calculators.htm

pdq67

I did search, but couldn't find any way to do it without pulling the heads. I thought I heard years ago you could get a close guess with the cranking psi if you knew the cam specs.

the head CCs aren't listed on mortec. The motor ate a cam and I'm going to stab a new one in. Don't really want to take it all apart, just trying to get a ballpark to see if it is 9:1ish like I was told so I can pick the right cam. Engine was built in 95.