Play around with the distributor, twist it both ways and see if that helps and, uh, GET A TIMING LIGHT! It sounds like you have too much advance. Disconnect the vacuum advance and plug all unneeded ports on the carb. Then you don't have to worry about the vacuum advance screwing things up. Do this first. Set your base timing to 12 degrees as a starting point.
You should also buy or borrow a vacuum gauge to set the idle mixture screws. Hook the gauge to a manifold vac source and tune the screws to get the highest vacuum, then adjust speed with the idle speed screw. Then put the gauge on the ported vacuum port and make sure it is at zero. If not, play around with the mixture screws again till you can get it to zero vacuum or close. This way you will not have any vacuum advance at an idle, you don't want that.
You want the choke on a switched hot wire, not a toggle. The current keeps the choke open.
406 Dart equipped.
12.20 @ 115.25mph
Bodydropped on 18" Boyd Coddington Timeless 5's