Thanks to everyone for your help and support on this concern.

The excessive fuel pump pushrod clearance issue was resolved with NO change to the noise. No worries, this needed to be corrected anyways.

I decided to remove the engine and inspect. #2 rod bearing was the cause of the noise. Hard to believe there was no change disabling spark for that cylinder. All of the other bearings look to have normal wear.

Hopefully, the crankshaft can be polished. Enjoy the pics!