'71 198 swap to a '76 225 - help identifying noise?

Maybe check the converter bolts.

Torqued them all to 22 ft-lbs per spec.

You do know the rods out of that 198 motor are worth saving. Even if only 5 of them are still good. There is always a market for the 198 rods.

Yes, the long rods are desirable, I do know. Any idea what a set would be worth? I was just going to sell the whole engine and let someone else dig them out. Don't have a ton of time right now.