i have put 85 amp alternators on both style of a-series (alternator on driver or passenger side), it's pretty simple, i use an EA falcon alternator which can be picked up pretty cheap at a wrecker (there is 75 and 85 amp models but both are identical to mount and wire)

the install also allows you to remove a lot of wirring, i have posted the details on the conversion before, let me know which side your alternator is on and ill give you a run down if you like