Rebuilt 340 knocking sound

Hilarious guys dont bother to read the whole thread before putting there 2c in....
Yes, a lot of that goes on. Good of you to step up with a documented yeardown and rebuild. Myself I would be curious to have a looksee. Like you without hearing but reading the OP and your observation and the description, I believe it is terminal in the current situation and needs to be aired out. No sense prolonging the inevitable.