I wanted to upgrade my 65A alternator on my Westy diesel to 90A to help in
recharging a second battery. I had a 90A WBX and a 90A Jetta TD (with the W
terminal) alternator. They are both the same mounting configuration. I
swapped pulleys with the Vanagon alternator so that the belt would line up
and mounted the alternator to the bracket. For the belt tensioning arm I went
to my FLAPS and got a chrome universal alternator arm by Spectre. I shortened
it about 3", drilled a new hole and mounted it using one of the injection
pump mounting bolts. The old belt is a tad short but I am using it for now.
For the B+ lead from the alternator to the starter + terminal I used #6
welding cable and had my FLAPS install the correct terminals. For the D+ (the
old blue wire) terminal I simply spliced in a new wire from the alternator to
the old connector near the battery. The Vanagon diesel has dead space behind
the stock battery to mount an Exide or Optima AGM deep cycle for a auxiliary
battery.
Hope this helps someone.

Ken Hunter
82 Westy 1.9D
84 Jetta 1.5D
89 Mitsubishi van