The thing that has to be done is to reposition the Alternator to the rear, so it is in the alignment with the AIR Pump Belt.
Then once the Alternator is in place, bearing in mind that the power terminals must be clear of hitting the head, and you have sufficient movement to tighten the new belt, it is all go from there.
The pictures I have attached are one I did on a '69 SDV, but hung the Alternator down low. It was smaller than the Original and suited that location.
As you will see, I modified the rear bracket by cutting off the excess material, and trimmed the front mount, and fabricated a piece to extend out to mount the front part of the Alternator.
The adjuster piece is one of the parts I had laying in my stash for future use, and not sure what it was from, but it isn't difficult to make one yourself.
The biggest thing is to ensure that there is sufficient clearance where the arm is close to the fan on the Alternator.