Took the Charger out for a short drive ( bout 10 miles round trip ) and noticed on the way home the ammeter was jumping a little ( positive). Didn't think too much of it as I hadn't driven the car for a while and figured the battery needed charging.

Took the car out for a longer drive ( about 30 miles mostly highway) and on the way up the ammeter read +20 the whole way up.

On the way back it was still around +20 then about 15 or 20 miles in started to go higher about +40 (almost pegged).

The car ran fine but concerned about overcharging.

Today I started the car and after warm up and the car idling the ammeter read just slightly positive ( normal ).

I checked the voltage at the battery before starting it was about 12.75V . While idling the battery voltage was 17.50 - 17.62 volts ( seems high to me ) .

I checked the voltage at the regulator at idle and it was 6.8-7.5 volts.
I checked the alternator at idle and it was about 7.8- 8.2 volts

I checked the ground to the voltage regulator ( using the bracket holding the regulator as one side and an open hole in the radiator support on the other side with the ohmmeter ) and got a good connection.

The car runs with a Petronix electronic ignition system, does this effect the type of voltage regulator I need for an otherwise stock 69 set up?
I've seen solid state replacement voltage regulators for sale, but not sure what's in the stock 69 regulator.

Thoughts?
Overcharging or not?
TIA