driftset

iTrader: (1)

So I have a stroked ls2. I just bought some prc ported ls3 heads. I want to bump the compression ratio up and want to mill the heads but I don't want to run into any ptv problems. The Pistons have -2cc valve reliefs in them. Could I safely mill off .030 from the heads? I plan to get a custom cam made for my setup too

DavidBoren

Did you know the combustion chamber volume of the ported heads you just bought? If you bought them used, I would definitely cc the combustion chamber before milling anything off, just in case they have already been decked. You could always clay a piston and measure exactly how much clearance you have, as well.

driftset

iTrader: (1)

No they're new heads. .005 was taken off just to clean it up. The heads are 70cc

MuhThugga

If the motor is already stroked, have you calculated what the compression would be with the heads as-is?

I made assumptions on a 4.005" bore, 4.00" stroke, and the piston being .006" out of the hole, but with the -2cc reliefs and a factory 6.0/6.2 gasket, your motor would be around 11:1 with the 70cc heads. If you simply went to a .040" Cometic gasket without touching the heads, you'd be at 11.4:1. How much more compression are you looking for?

driftset

iTrader: (1)

The Pistons are .003 out of the hole. I want to be at 12:1. Yea I plan on getting thinner head gaskets. I really want to get closer to 12:1 while I have the opportunity. I just don't want to have any ptv clearance issues

MuhThugga

Your best bet is to measure your PTV clearance. Are your pistons' reliefs wide enough for the larger LS3 intake valve?

And why are you shooting for 12:1?