Totally disgusted - flat cam

[piecesparts]

My guess is that your oil type was not the issue with the failure. Especially 500 miles on the engine. The fact of the matter, is that you said that you were using a break-in oil, so you should have been protected. The discussion for zinc in the oil is a good item to consider. That would leave two possibilities---the cam material failed or you could have had an oiling passage failure. I would go throught the whole set of oil galleys to make sure that they are clean before reassmbly again. Been there, felt the pain.