While I agree the bearings are likely toast as a result of the motor pumping some iron infused oil thru itself after the original cam failure, which is probably why the hot oil pressure is low.
However, the motor now has a roller cam in it, with I assume unrestricted oiling to the lifters.
Sometimes there can be some pretty big leaks around the roller lifters...... especially with 340’s....... on the tops and bottoms of the lifter bores.
“If it were me”, and I was of the mindset where the motor had to come out and apart anyway....... before I did that....... I’d pull the intake manifold while it was still in the car, and run a priming tool and check to see if any of the lifters were hemoraging oil from the top or bottom.
To really see what’s going on you’d want to watch each lifter through it full range of travel and be looking for oil to be coming out of the top, or the bottom of the bore.
The biggest leaks “usually” occur in the area of full lift.
If enough of them are pretty big leakers, it will def impact the oil pressure....... especially hot.
While the bearings may be shot...... that may not be the only problem causing low oil pressure.
Best to check before you take it apart.
None of that should have any impact of how it runs though.