Rebuilt 340 knocking sound

MoparLeo said

2 things you can do without tearing it down. Pull the valve covers, disconnect the coil wire. Use a remote switch on the solenoid wire to rotate the engine and watch the rockers. They should all rise and fall the same amount. Bent push rod, flat cam lobe will show minimal movement. If that checks out ok put it back together.
Get a good set of insulated plug boot pliers and/or good rubber gloves. and start the engine. Pull the plug wires one at a time until you hear the knock go away. That is your bad bearing.

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With that much metal flake in the oil, there will be crud all over in the engine. All the bearings will be embedded. The only proper solution is to air out the engine and inspect every part. That way all oil passages can be cleaned with a rifle brush. Personally, at this time I would consider a swap to a roller cam. Takes oil selection out of the equasion.
With that metal in the oil, low oil pressure and knocking, running it more only damages more stuff, with the resulting cost of replacement.