Main Bearing replacement guideance

Hi Herb. Just a question if you don't mind. Did you actually find the cause of the oil pressure loss?
Yes....
The Oilpan meet the bridge deck down the road from the house.
I was logging my FAST EFI when it happened and the oil pressure dropped to Zero when the two meet.
Then slowly came back up some as I drove back to the shop. Plus the bearing clearance was on the loose side to begin with.