I should say I have assembled and disassembled heads lapped valves and all that kind of stuff. On a $50 318 and some old 360 heads I had laying around. I was mismatching different Springs and different retainers from the original 318 heads over to the 360 heads with some 360 intake valves that I had from a different head completely. Slept it all together it ran like a top and even posted a video of me drag racing it...