Gonna upgrade to Weisco, KW, or Ferrea valves. Not sure which yet but my question is with stock sized valves either brand, do they all use the same size guides? Is the OD on all the stems the same? I know im going to need to shorten the intake one. Well i found an intake guide already shortened that im going to order. I believe its KW. Im replacing all the guides because they are 19yrs old so im sure they are worn at least some and while im there.... Why not?