I am working on a 1985 Ford Mustang 5.0 H.O. and i am about to go from a stock cam to a x303 Duration int/exh 224 Lift int/exh .542 and 107 Lobe Seperation am i going to run in to Piston to valve problams. I'm going to change valve spring on stock heads and the right length pushrods. If so what is max lift on a 5.0 H.O. motor with stock pistons.