Note 1: 2-wire and 3-wire alternators seem to be identical, the only difference being how many brown wires are connected to the plug and hence the alt. Where two brown wires are used, one thick and one thin, the thin wire is a voltage sensing wire. Later models had two thick wires, these are both output wires for a higher current carrying capacity.
Note 2: V8s used the 1971-72 system i.e. a single thick brown. This is connected to a stud under the RH toe-board together with the thick brown from the ignition switch etc., not to the starter solenoid.