70 Duster runs rough or dies when up to operating temps

Sounds like its leaking or driven in partial choke mode. Have you ever tuned from when its rough idling and dying? Or do you just set it in choke and drive off?

Try 4 turns out on the idle screws.
Try a little wd40 or water on spray bottle around the carb base to check for a vac leak as well. Do you have the flat adapter plate under the carb or this one not need it? I prefer holleys..so my memory isnt crisp on the plate requirement.