I'ts not the .550 lift that will hurt you, it's the LSA and the duration. I think the max LSA and duration for a stock pistoned engine is 112 deg LSA and 225 deg at .050 with around a half inch of lift. Which in most cases is fine. Most of the issue is all in the valve timing. You could run 1 inch of lift if you could get the parts in there to make it live, and as long as the valve action was fast enough to close the valve in time so that it would clear the piston. I don't think a .030 eyebrow would hurt but one of the Inertia motorsports guys should be able to answer this question with more accuracy. I have aftermarket pistons and a big cam in mine so I havn't tried to do what you would like to accomplish.:thumrigh: