stroker blues

Run high zinc oil even with a roller.... Had a couple bouts of the same situation but in my case the push rods didn't bend, they broke the (aluminum) rocker arm by jamming underneath. Sounds like your push rod came out (too short, not adjusted properly or rubbing on the head), bent under a rocker and allowed the lifter to come out, dropping oil pressure. Something bent the PR so carefully inspect the rockers on that cylinder and the rocker shaft before putting it back together with a new rod. I would also check the springs and retainers, at least on that cylinder.