Knock Knock!

Crushed my crossover pipe a few too many times and had to replace it. Was kind of loud. Noticed after putting in the new cross over, that I had a knock that could be heard from 10 feet or more (my muffler is middle loud). Listened to the bottom of the motor and the sound seemed to be coming from 5 or 6 near the bottom. Had to change out the crank seal anyway, so decided to change out the connecting rod bearings. They plasti gauged out to within spec, but there is a significant scuff on the top bearing on every cylinder, but they aren't that loose. Have checked the flex plate for out of round, seems OK, torque converter bolts are tight.
Any other ideas? I recently changed oil to Castrol fossil, because I couldn't find synthetic on sale and it was leaking about a quart a month.
Compression is 150 across the board, wrist pins seem tight, plugs look a touch lean but not excessive. One cylinder looks like it may be passing a very small amount of oil past the rings. one of the plugs looked like it may have a very small amount of oil crust in places.