90A Alternator application

[Indiana_Red@hotmail.com (Ken B)]

Somehow I ended up w/ 2 alternators.   Both 90A.  The main difference is how
they mount up but I don't know why.  One has 2 "ears" for mounting to the
big cast iron bracket that so many of us like to chop when we move the alt
down to the A/C comp spot. P/N 0 120 469 689 709
The other one has the "tube" type mount that looks as though it goes onto a
brackett with "ears". Kind of the opposite as before. P/N 0 120 469 727 732
 The former is the one that came in my 16v Scirocco w/ a/c.  The latter I
got from Ebay supposedly from a 16v roc'  unknown A/C or not but I think it
had the longer pulley on it.
I have switched around the pulleys trying to line the Vbelt up after
eliminating the A/C and PS that Im not sure about that part.
What is the standard mounting hardware have to do with the engine or
accessory or trans options?  What do I have here?
Thanks as allways
Ken
1979 Scirocco  "McFly"
16v conversion "...it's working....It's WORKING...!"
tracing electrical gremlins now...
VORTEX:  "Indiana Red"