So I picked up a 1970 Duster today, got some newb questions

The voltage limiter or regulator is on the instrument panel circuit board mounted on the rear of the instrument panel. You will have to remove the panel. Disconnect the battery first. The ammeter guage connections are held on with nuts, I believe. Disconnect the speedo cable and bulk connector to the circuit board. The limiter is the small rectangular can. You can also check for burnt traces on the circuit board. The bulbs are in the black twist out bases. Mike