[Sirrotica]

FWIW, I once had a 301 that I slammed together that the crank was .010 under on the rods only from the factory. The mains were standard. I put standard bearings in it inadvertently and drove it about 50 miles. Other than low oil pressure at idle it was surprisingly quiet and when I took it back apart I finally realized that Pontiac had put it together with a undersized crank with Moraine factory bearings.

I just swapped the standards for .010 bearings and it was fine. No metal transfer, and the rod throws were clean, and round. Now this was just highway driving, and not hammering it, but with .010 + oil clearance I was quite surprised there was zero damage and lack of any unusual noises.