Overcharging Problems?

First, you should be measuring voltage AT THE BATTERY not at the alternator stud.

Second, IF the battery is overcharging, it could be one or MORE of several things

I've posted this before, it's a big big problem

Do you have fairly "stock" wiring still using the ammeter? Still using the firewall connector?

Before I rewired (part of) my 67, I had done a TEMPORARY ammeter bypass.

EVEN SO there was ONE VOLT drop from the battery through the bulkhead, through the key, back out through the bulkhead, and to the "dark blue" at the ignition

Because this "dark blue" "ignition run" ALSO feeds the regulator AND IS THE sensing lead, this means that this ONE VOLT DROP then ADDS to the regulator setting. That is, if the regulator would have normally charged at 14, this one volt drop causes the regulator to ADD ONE VOLT so the battery ends up at 15.

So do some checks.

With your engine running at "low to medium cruise" do some tests first with all accessories (including fans) OFF and then again with lights, heater, or fans ON

SO stab one probe of your meter DIRECTLY onto the battery NEG post. Stab the other probe directly onto the ground frame of your regulator. Make sure and STAB it through the paint.

You are looking for a VERY low reading, zero is perfect, anything over about .2V (two tenths of a volt) is too much, and indicates the regulator ground needs work.

Next check the hot side. Once again, you are checking the drop across the wiring harness from the battery, through all the wiring and back, to the regulator.

Stab one probe directly onto the battery POS post. Hook the other probe as close as you can get to the IGN supply to the regulator. Often, the blue at the coil resistor is close enough.

Here again, you are again looking for a very low reading, and over .2V is too much.

By the way, after my "partial rewire", I'm using a fuse / relay box out of a Caravan, and using one relay each for, "all ignition run components," one for pump, one for low beam and one for high beam.

My regulator is magically right back where it ought'ha be.