sources of engine knock?

[robert2323]

1969 Chevy C20 with GM Goodwrench 350. Frustrating situation. Bought a remaned distributor, installed it and when I fired it I had an extremely loud engine noise. Sounded like a sledge hammer banging against steel. Diagnostics being my weak suit, I assumed rod knock. Pulled pan and checked my bearings. No metal flakes anywhere, found one bearing with the slightest of play. The bearing had a wear spot in it, so repaced it. I installed everything back togheter, new oil (10w30) and filter and fired again. Still loud knock. The parts guy at Kragen said there was no way that distributor would make a loud knock. Being baffled, I've pulled heads to look for broken piston, but nothing obvious there either. I have a friend giving me a chevy 350 distributor today (after buying a head set and reinstalling top end). Any advice would be graciously welcome, because I'm at a loss, feeling like a jackass taking apart a perfectly good long block.