So I ended up replacing my intake valves with stainless (06 450) I am trying to get the valve clearances figured out. I installed all three valves in the order they were in the packaging, the middle valve has a different part number than the two on the outside so I was careful not to mix them up. But here is my problem, the middle valve has no clearance (even without a shim) and the clearance one of the outside valves is pretty far out (needs a 215 shim). My original problem was bad valve seals and one valve stem lost the tip so I doubt it is a problem with the seats. My thinking is that those valves were mixed up in the packaging. But I really don't know what the difference is between the middle and outside valves so that is just a guess. Any ideas?