[tubman]

I had a similar problem with my '51 Ford, only it was more of a rattling noise than a knock. Like yours, the engine performed well and had excellent oil pressure. After a while, I decided to not take any chances and swapped in a '51 Mercury engine that I had. Because the pans were different, I had to swap them between the engines. When I cleaned out the Ford pan, I found a chunk of the rear main thrust flange about an inch long lying in the bottom of the pan. I know that's what it was because I had a set of new in the box bearings I could compare it to. I talked to my machinist about it, and he said it might be a defective bearing, but most likely, an "assembly error".

Not saying this is what you have, just giving an example of what can happen with these old engines.