This will be on a stock LQ9 6.0 block.

Which would be a better gasket to go with? Meaning, is the 4.03" too small for a 4" bore or is the 4.135" too big?

A. Cometic 4.03" .045"
B. Felpro 4.135" .041"

 

I think it would depend on what quench height you want to maintain and what your piston deck height is.

 

Well my deck height is about -.007
I have no idea how to calculate quench.
I was more concerned with DCR & SCR which will be around 8.54 DCR and 11.38:1 SCR.

Oh, this setup will be with Patriots LS6 heads (64cc) and TR230/224 cam.

 

Quench is easy. It's your gasket thickness plus your deck height. So in this case, .045" + (-.007) = .038".
Optimum quench, as a hotly debated item, would be between .035" and .040", so a .045" gasket will give you ~.038".
I would need bore and stroke, and cam advertised specs, along with ICL, advance, and LSA to give you DCR and SCR from my calculator.
Assuming advertised specs of 280 intake duration and 273 exhaust duration, with a 110 ICL and 114 LSA on a stock bore and stroke LQ9 I get:
11.36:1 SCR with an .045" gasket (4.03" bore)
8.63:1 DCR with an .045" gasket (4.03" bore)
11.42:1 SCR with an .041" gasket (4.135" bore)
8.68.1 DCR with an .041" gasket (4.135" bore)
This is from my calculator and assuming a 114 LSA cam with +4 advance. DCR will decrease as LSA and/or advance decreases.

 

Cool

Actually the LSA is 111 +0 with 110.7 ICL according to the cam card.

 

Here are the values I came up with when I plugged your numbers in. Not too much different.
Hope this helps.
11.36:1 SCR with an .045" gasket (4.03" bore)
8.59:1 DCR with an .045" gasket (4.03" bore)
11.42:1 SCR with an .041" gasket (4.135" bore)
8.63.1 DCR with an .041" gasket (4.135" bore)

 

Hey, thanks alot for your help Arkay99.