392 stroker oiling problems

I'm not an expert by any means but hopefully this might help. I had a similiar problem on my 360 first go around. Didn't actually spin the main bearings but it did spin a rod bearing and the mains weren't far behind. When I took it apart the main bearings were collapsed and would no longer stay in the block on their own. Talked to my machinist who is also a small block Mopar racer and we figured out it was cause I was running too much total timing (about 40 degrees). My bad.

It sounds like you did all the machine work correctly. And since you said your not seeing the pressure drop on the gauge but it's eating the main bearings I would look at total timing to see where it's at. If it were starvation I would think you'd see the pressure gauge drop.