One point I will mention,something I learned the hard way was that if building a performance engine check 'all' the spec's. on the pistons before you buy.Some aftermarket piston mfr's. make 'replacement' pistons to sit lower in the cylinder than the factory pistons.This can reduce engine compression considerably and of course reduce power.But that can be bad or good,depending on intended use of the vehicle,power output desired,etc.,etc. But again,depends on how much performance you desire.If your building an everyday street car most would probably suggest staying under 10:1 and that would be safe 'and' practical.