Please help diagnose my sound. This has to be something pretty bad. I have a freshly rebuilt, bored, TBI 350. During the intial start up and cam break in I boiled over the coolant, but shut the carn down quickly. Now (after fixing the cooling problem) when I start the engine it will run great for about 20-40 seconds, then a very loud metal on metal rubbing/moaning sounds come from the engine. Of course I immediately shut it down. I can restart the engine and it will repeat, run great 20 seconds, then same thing. The sound is horrible, vibrates the truck. I have very high oil pressure (gauge ends at 60 psi and gauge stays pegged) I'm not the person who had the engine rebuilt so I don't know if a hi-volume oil pump was used. Something is clearly heating up in the engine and then losing tolerance and rubbing. I assumed a spun bearing, but after reading a bit sounds liek spun bearing makes clicking noises and cuases low oil pressure? This is definitly not clicking and I definitly don't have low oil pressure. What could this be? Does my high oil pressure mean my oil is blocked from getting somewhere? The engine must be trashed, becuase the first time I ran the engine I made it through 10 minutes of the cam break-in before it over heated so if something was starved for oil, it is ruined by now. Any ideas?