Yes, the camshaft notches will be an issue if you are using a camshaft for a 250 in a 292 engine. Did you inspect the camshaft for evidence of contact by the connecting rods, should be easy to spot on either the connecting rods or cam barrel. Another source of the knock could be from excessive cam thrust. This is often overlooked by many when rebuilding these engines and will produce a knocking/thumping sound that is hard to find. Did you replace the thrust plate and thrust ring when you rebuilt your engine.
