John do you have a good aftermarket oil pressure guage in the car ? I'm thinking you have some oiling issues, Bad bearings, flat cam and possibly bad rist pins.
I had no problem with the rockers galling or any knocking/tapping when it ran. I also primed the motor before initial start-up with a priming rod in the oil pump with the distributor out. I had the valve covers still off to verify that oil was getting up in the heads. I (had...) a new Melling stock volume oil pump. The pressure switch is new with a working factory gauge. Plus it never ran hot and the oil looks like new. Except for all the shiney stuff in it.
I'm into this thing for my lungs at this point..... Me thinks I need to re-do the block. At this point I'm ready to cry. :(