Most of the shafts have a larger hole than the 5/16 bolt that goes through, it moves fine with the shims...aside from stacking them that is.
Tightening them unevenly is what I've seen do some harm.
You're absolutely right! But in my case with this ported slant 6 head, I put 318 valves in it. They are about .300" longer than the stock slant 6 valves, so that required a lot of relocation. I haven't fitted the shaft yet, as I still need to get the intake valves back cut. But it's nice to know to "look out" for that. ;)
