I should know this, but is there any difference between n/a and turbo heads (apart from casting revisions and the intake cam)? Reason being, I'm rebuilding another 7M, and I have a good condition n/a head, I was wanting to use (with my turbo cams)...are the valves the same composition and size in both flavors? Anything else I should concern myself with aside from the usual, ie hardness, straitness, between the two? thanks for your time. I'll do a mild p&p, and use my new comp cams springs. Nothing exotic.