A lot of people are using those universal replacement alternators with the rectifier and voltage regulator built in.
Maybe someone will chime in with the exact information. From the many time I have seen them mentioned in threads here, it is a Datsun type, available at most car parts stores, and priced around $50.
Or if you are a do-it-yourselfer, get out the voltohmmeter and see if it is simply a shorted diode in the rectifier plate.. That's usually the problem.
rScotty