Just get the bracketry off the front of a non ac xj and it will bolt right up.
Probably have to change the belt accordingly.
Pick you part had a few xj's last time I was there. Might be worth a trip.
Or call jeep stuff and they will pull everything for you and have it sitting there for your pick up.
Jeepstuff is 681-jeep
hth
Have you done this? Every XJ I have seen wether it has AC or not has the alt at the bottom. If it doesn't have AC then there is a idler pully in its place and everyting else is the same.
If you are having problems with the ALT dying after being in mud, change the indexing of the case so that the brushes are at the top, then the crap will freely drain out the bottom.
I was going thru 2 alts a year untill Capt. Crunch told me to do this. Since I've done it no more problems.