Isn't there an equation that says if you take X amount off your heads, your CR raises by Y amount? And also, isn't there one that says for every .5 raise in CR, you gain 10hp? Am I even close?

 

There really isn't an exact formula for that as far as I know. No one has figured the exact area for the chamber, which would be needed to make the formula accurate. Its going to depend on the head casting (5.3, LS1, LS6, 6L). Most people just estimate how many ccs are removed when X amount of material is milled off.

 

I've heard common thought was that every full point of compression is worth a 4% change.

 

So if I raised my CR by .5 to 11:1, I would gain roughly 20 peak HP (400rwhp currently)? With that said, how much would I shave off my LS6 heads (64cc) to gain .5 CR?

 

Ok I did a broader search and found the answer I think. From what I've learned, taking .030 off will raise CR to about 11.1 or so and will change the cc size to about 59CC.

Now I'm just trying to figure out if I'll need shorter pushrods. Since most aftermarket cams have a smaller base circle (needing a longer PR) and I mill the head (needing a shorter PR) then stock one's should work correct? Everything should be about even and the hyraulic lifter should give me a safe + or - area.