Msd 6al install. Now over charging

FIRST THING we need to know is WHAT YEAR MODEL are we working on?

You may have damaged the ECU modules because it was ALREADY overcharging.

WARNING: I am BIASED against "one wire" alternators, ESPECIALLY in a situation like this. "It might be" that it fixed the problem, or IT MIGHT make the problem WORSE, depending on what that problem IS

The most prevalent cause of over charging is VOLTAGE DROP caused by POOR CONNECTIONS in the wiring harness. These can be numerous and add up. The "popular" guys are the BULKHEAD CONNECTOR, the IGNITION SWITCH connector, the IGNITION SWITCH, and the AMMETER CIRCUIT

Other causes are (rarely) the voltage regulator, poor grounding at the VR or poor grounding between engine/ battery/ and body. Rarely, the battery itself

ANOTHER LARGE NASTY CAUSE on 70 and later cars is damaged/ broken brush holders which ground out the "green wire" brush and cause the alternator to charge "full output" regardless of the regulator

If you have not done so, go to MyMopar and download a free service manual, and also the aftermarket wiring diagrams in the wiring section. these diagrams are not always very complete or detailed, but can be easier to follow

YEAR IS IMPORTANT. Especially around 71/ later there were changes almost every year. 74 has the oddball "seat belt interlock"