We already told you what was wrong. The bottom of the lifter was concave because the cam lobe was wiping out and did that to the lifter.Seen it a zillion times. The motor needs to come out and be redone,all those metal shavings have been circulated thru the oiling system and are now imbedded in all the bearings.
I know you hate to hear that,but it is fact. And when its put back together it would be wise to go with a roller cam setup because the oils we have today will not support flat tappet cams.