Overcharging 68Dart...need some short fused help (pun intended:)

Let's back up here and start over somewhat

1...Smoke is NEVER good
2....You may either have a wire crossed or somehow hooked into the VR / field circuit, OR the alternator field may be partially shorted and drawing too much current

If you do not have such, wander over to MyMopar and (free) download yourself a factory service manual. In section8 under alternator is a procedure to measure field current draw of the alternator. We need to know what that is.

Do that BEFORE you install another VR

3...Next I would try wiring in the new VR "direct" temporarily, that is, wire a new temporary wire direct from the VR F to the alternator field, and "temp" a wire direct from the VR IGN to the battery. Disconnect the VR IGN from battery when not running.

Test the output and voltage/ etc as to battery voltage, and alternator drop between alternator output and the battery +

Make CERTAIN the VR is grounded.

4...Finally if this all works out, no smoke, proper system voltage, etc, you can start backtracking and implementing te thing back into the system, carefully checking wiring each step of the way