like maybe focing the impeller to run out of "true" and cause that uneven wear ?

No impeller on this oil pump. The rotor, on the other hand, probably would not be under too much stress, it would just run dry.

Steve, when you pulled the valve cover, was there oil sitting up there? Did it look "fresh"? Was there galling on the cam journals? If there was an oil starvation problem, it would show up there first.

Did you spin the oil pump in the correct direction when you tested it? You hadn't drained the oil first, right?

Michael