I would suggest contacting someone like Best Machine,,Hughes Engine or other Mopar savy shops and see what tooling they have /use and their opinions on your issues.
Obviously something is wrong.
Not a typical failure in my opinion.
Well I can tell you this, it is a very typical failure, I have been racing Big Block Mopars for 35 years and when you start pushing the limit of a stock block there are tons of issues. Cam bearing failure is probably the #1 thing wrong with B/RB stock blocks.
Been racing and around Mopars for over 50 years, I can’t remember the last time I saw a cam bearing failure.
Super Stock, Modifed Production, Stockers, even fuel cars.
All using commercially available bearings, with nothing special being done to the bearings or cam.