If you're using the same cam, here's something that happened on a BBC. Plenty of oil clearance, and straight. Ate bearings almost as soon as it fired up. The problem turned out to be tiny heat cracks in the cam you couldn't feel with your hand. Showed up in the polisher. New cam , no more instawipe bearings. I mean smoke coming up through the valve cover with almost. 003 oil clearance. Spun by hand like a top, but as soon as pressure and heat hit it,,,presto saw blade