I'm sure this had something to do with the looks of the bearings.

Right. Don't know for sure why stuff was done

Bores were out of round and tapered. Although I did get them hot

Do you know what the bearing clearances were? .0035? Bigger?

And there were .180 of small block shims under the springs.

I was referring to the detonation on the Pistons. It will hammer the hell out of the bearings.

What do you see in the way they look? Are you referring to the dirt that sutphen mentioned? Trying to at least learn a little from the experience * edit just saw your reply. No one else mentioned detonation. What are you referring to.

Comp was 9.0 , 36 ° timing, 93 octane

Post #7. 1st photo.

The top of the piston in the one pic looks like it was sand blasted. That from detonation. The pic to the right of that one looks like it has a small chip missing around the outside (exhaust side) that's detonation. If you have the Pistons out and flip them upside down I bet they have burnt/ baked oil on the backside this is due to detonation. You probably also have black stripes on the sides of the Pistons this is from detonation. That's why it is often referred to as Black Death. Do not re-use those Pistons. At a minimum you need to carefully measure the ring gaps in them. What happens when they detonate is it shakes the hell out of the rings and the ring land gets oblonged in the back of the groove. Also when they start shaking you loose seal and end up with the black stripes on the sides of the Pistons. Detonation will eat the bearings right out of a motor. Make sure you have the main line checked carefully as well as the deck of the block (front to back side to side). It can and will move things all over the place.