I have a couple questions to ask a friend of mine recently purchased a 1967 ford Ranchero and we want to stroke it by putting a scatt remanufactured crank. The measurments of the crank are 4.500 stroke . This turns the engine in to a 473 which I get. What I wanted to know was if we do that do we need to change the rods, pistons, heads and if we should bore the engine while we are at it. Also will we have any clearence problems with the valves and the pistons.