Dodge Dart carb tuning issues.

The kickdown "should" float enough that it won't hold the throttle open. If by chance it does, that may be the issue? As far as the choke, It depends on the type, manual or electric? As long as it's open all the way, there is a separate fast idle screw associated with it on the passenger side of the carb. You need to make sure that it's not touching the graduated cam when it's fully warmed and the choke is open. Let me know what type choke you have, and maybe I can find a pic to illustrate it.