I'm pretty sure that Gates makes the kit for Isuzu. My Gates kit came with the directions that said "orient the Isuzu writing on the belt", there was no Isuzu writing on the belt. Also, my kit didn't come with the new tensioner, just the pulley so you may have to order that separately. If you decide to do it yourself PM me and I'll send you a short PDF that I did up with a couple of hints that made my installation easier.
Current caretaker of The elusive 2001 "Pearl White" VX - The last one.
1988 BMW 325ic