HotRod Lincoln speaks the truth!

Plasti-gage all the rod and main bearings as part of the "post mortem" &
Record all clearances.

When you clean & re-build make sure you do it all over again….. & don't button it up till they are all within spec.

It seems to me that some mismatch has occurred between between machine work and bearing size selection……
Most importantly, Keep the Faith …. crap like this happens more often than you might think!
mike