GB will hopefully chime in here, but in the meantime I'll add my 2 cents. What kind of oil pressure does it have, and how bad does it knock? If it knocks while idling, you can try pulling plug wires one at a time to see if you can eliminate the noise. If the noise goes away when one specific wire is pulled you most likely have found the culprit. There used to be a 2 way pump that you'd screw into the plug hole that with the valves closed in the cylinder you can push and pull on the pump handle to make the rod or wristpin knock w/o running the engine. The next question is once you identify it you'll have to drop the pan, and pull the guilty bearings and look at the journal to see if it is scored or dinged, and look to see the same on the bearing. If the journal is good, and you had decent oil pressure when hot you may be able to get buy with replacing the bearing, but I'd plastiguage it to make sure that you're within tolerances.
I'm sure other folks here will provide some guidance. I'm doing a motor job on my 78 Dodge w a /6, and I'm trying to avoid unnecessary machine shop work too. Mike