Ive been thinking about the spun rod bearing. One thing that crossed my mind is that maybe the reason is that I used to thick oil, 15W20 and ran to much oil pressure in the engine. Cold the oil pressure was 100psi and once engine got warm it was about 60psi. Weirdly the oil pressure did not go up by much at high RPM, about 75psi @ ~7000rpm.

The clearances were/are quite loose in the engine, its an old Pro Stock engine. The bearing clearances for main and rod bearings were, if my memory serves me right, in the .0025 something (I cant find my rebuild memo). I left the clearances where they where when I put new bearings in it, clearances were/are a tad loose, but its an old race engine, and my plan was when I bought the engine, that Ill do a service and drive it as is for a season or two, then do a complete rebuild of the bottom end.

..Any ways... The thing that came to my mind is that was the oil to thick and the pressure to high when cold, could that have caused the bearing to spin??? So what do you think, did I up???

/Tom