How did you break in the engine rebuild and was this a new cam, reground cam, or used stock cam? How many miles before damage and what kind of damage? "Appears" is the operative word. I'm trying to find out what's really needed. No offense. It's in the details somewhere. I saw the guys on Fast 'n' Loud destroy a cam in a rebuilt engine, supposedly because they used cheap oil and a zinc additive. It was a push rod engine. They got it rebuilt and used the "special break-in oil with zinc already in it" (Brad Penn?, couldn't tell) and went on their merry way. The car probably has 10 miles on it by now, and who knows, may have destroyed its cam again. Anyway, I see three regular oils with no major issues, two "can't hurts", a break-in plus a few oil changes, and a destroyed cam shaft (reason unclear), so far. Not judging or drawing a conclusion just collecting stories.