From what I can tell, the stock compression ratio is 9.5. Has anyone increased their SCR to improve driveability out of boost? Would there be any gas mileage improvements in doing this? The reason I ask is I'm looking into getting 243/799 heads and having them milled, and can mill them to basically whatever SCR I want. I'm leaning towards stock SCR, but was curious if there is an argument for otherwise.

My setup will be a 76mm intercooled KB kit, LS9 gaskets and ARP head studs, 212/212 114 LSA cam. I am limited to 91 octane here in CA. Meth injection is possible but I would like to avoid it. This is a daily driver, looking for good driveability and fuel economy out of boost, and around 600 rwhp

 

Running 91 I would say anything higher then 9.5 is a bad idea. Your going to need some boost to get you to 600 wheel.

 

Yea, if you were looking for a lil lower HP, you could run higher CR with less boost and make the same power.
but 9.5 is a good target to shoot for.

 

Thanks for the help. Does anyone know the following values for a stock 5.3L so I can do some compression ratio calcs:

Head gasket thickness, compressed
Head gasket bore
Combustion chamber volume
Piston dish volume (or is it flat?)
Piston deck clearance

Thanks!

 

Anyone know the above specs?

And since 91 is the best I can do, should I consider a lower compression ratio?