Why wont my alternator charge

^^READ CAREFULLY^^ What Bobzilla posted

Up through 69, alternators should have ONLY ONE field terminal, the other brush is factory grounded with no accessible terminal

HOWEVER it is popular nowadays for rebuilders/ sellers to sell you 70 and later alternators which are properly called "isolated field" (not "dual field") and which have TWO insulated brush/ field terminals.

As above, if you have the original type 69/ earlier regulator, you must ground one of the two field terminals. Connect your green field wire as normal