Piston to wall clearance than a stock engine (as are most aftermarket/forged pistons). I'm gonna go out on a limb and suggest that there isn't a problem. I'd guess that the unbalancing of the engine by unplugging a coil+greater piston to wall clearance=RATTLE. I would call Kyle at IPP and ask him if it's a problem, I'm sure he'll help you. Good luck, Mark