Unless you're going for exact correctness, almost any Chrysler B/RB power brake vacuum fitting, with "one branch" of the correct vacuum line size, will do. Salvage yard is a good place to look. Plus the "HELP!" rack at the auto supply.
The small vacuum line runs the hvac system actuators.
Next time, if you have a reluctant-to-release vacuum line, use a sharp knife and put a short slit lengthwise in the hose, where it doesn't want to come off. After that, use a pair of pliers and twist the hose to break it loose, then remove it. Cut the slit area off so you can hopefully re-use the hose. Maybe soak it in some rubber lube for good measure, to hopefully soften it up a bit?
CBODY67