on a 406 .040 over with vortec heads also will i be able to run pump gas

 

CR depends on the pistons (dish or dome volume), deck clearance, head gasket thickness, in addition to CID and chamber ccs.

These guesses will use the "spec" for Vortec heads, which is 64cc; your heads may vary.

If you have stockish pistons with a 18cc dish, and they're .030" down in the hole (typical stock), and you run a .039" head gasket (FelPro 1014 for example), your CR will come out to about 9.6:1.

On the other hand, if they're flat-tops with typical 6cc valve reliefs, zero-decked block, and a .018" steel-shim gasket, it's 12.3:1.

Pretty wide range there.... from pretty comfortable with pump premium, to no way in Hades.

Sounds like you need to gather some more info in order to be able to make a more nearly informed decision.

 

thanks for reply sorry i forgot they are flattops with 2 valve reliefs