I agree with IceMan.
I used to want to install a serpentine system on my '81...I think it really dresses up the engine bay and makes it look much neater. However, after talking with various guys, including a man from Australia who installs 6.2L's into Outback trucks, I came to the conclusion that the v-belt system is just as good with one added bonus: you can take one belt off and keep going.
My aunt and uncle used to own a '91 'burb. Their a/c compressor locked up while on a trip, and they had to have it towed....couldn't drive it with only one belt running everything. They had it fixed, drove down the road a ways, and it locked up again. Had to be towed again. If they had a v-belt system, they could have removed or simply cut the a/c belt off, and kept on going.
If you do want to go to a v-belt system, you'll need everything: alternator, ps pump, a/c compressor, probably a vacuum pump, and a water pump. The water pump runs backwards in a serpentine system. The later 6.5L's with serpentine use a belt-driven vacuum pump...don't know if they had any applications that didn't.
Casey