Thrust Bearing- Abnormal Wear

To answer a few questions:

The 69 Dart is a 4 speed. I've only had the car for a year so I can't say what happened before that. It had a broken transmission mount (maybe caused by a big block fork instead of the small block fork) and really bad clutch chatter.

The 340 does not have screw in ARP studs.

I will have the thrust surfaces of the crank checked by a machine shop.

Thanks for all the advice.