[Captkaos]

A blown powervalve (fuel enrichment) will cause the motor to run rich all the time as it will be dumping gas all the time because there is no vacuum to keep it closed.

Jets are the same secondary vs primary for a Holley. You will still have to remove the bowl to get to the metering block to remove/change the jets. Based on your symptoms I would say your powervalve is ok. Most Holleys now come with "blow out" protection in them now. Not sure about the 4160, but... I would try rejetting it. I would also recommend setting the idle and mixtures with a vacuum guage.

Where is your base timing set? How much vacuum advance are you running? I would say start at about 10 degrees mechanical advance and work your way from there.