Did you or can you verify the TDC on the balancer and the timing cover to make sure what actual ignition timing you have now?
If not get some help to do that and then let us know what you found.
Also verify the firing order on the spark plugs wires and distributor cap are correct, 1843
6572 scope up twocents

Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)