I've used b7 valves in a z6 before just because they sat flush with the combustion chamber. Only problem is the stem is longer and has a different retainer height, so if you're not careful and run the wrong spring it will bind up. I don't remember exactly which springs I used, but I think I ran an aftermarket a6 spring. Also the lash adjusters will be almost all the way unscrewed just to even come close to the proper clearance. IMO not worth the time, better off going and ordering a few new ones from the auto parts store.

 

i want what they are drinking lol

 

while a B7 valve fill fit a Z6 head, you can't proper seat it.