[redmodelt]

I can't give a mileage to check not knowing how the engine was setup in the first place, babbitt used, clearances etc, but if you are going to check the mains and rods I would suggest pulling the engine. The No.3 main is a bugger to do under the car, can be done. No. 1 and 2 you need to reach up and turn/hold the wrench while holding/turning the main bolt or have a helper. Still a bugger to do multiple times while checking.

The mains could be ok and the rods need attention, which would be doable under the car.

With that 65+LB weight hanging off the end of the crankshaft, there will be some bowing, down for the 3rd and up for the center.

Have you brought the engine up to temperature and used a stethoscope to listen for noises yet? Could be lifters/valves timing gear etc.