Aaron1989

I have a 00' Lq4 motor with stock dished Pistons. I just bought some stock 243 heads to put on it. I have a tick performance SNS Stage 3 cam.(235/243, .630"/.610", LSA 111+2) if I put the stock heads on the motor with a stock gasket what would my CR be? And would I be able to mill them .020" or .030" or run a different gasket for more compression without running into PTV issues with the SNS cam? I'd like to have a good CR for a strong N/A application while still being able to run 93 octane.

Martin Smallwood

iTrader: (2)

Your compression will be roughly 10.2-10.3:1 with stock un-milled 243's and LQ4 short block.

I would not mill the heads at all with that camshaft. I designed it for maximum performance with a stock bottom end engine that did not have milled cylinder heads, or cylinder heads with larger valves. If you mill the heads or install larger valves you will have to fly-cut the pistons to ensure adequate piston to valve clearance.