I set my 235 up a little differently than most. I fabricated an alternator mount that goes on the passengers side of the block and left the space above my low mount compressor for my future power steering pump. By doing it this way, and using a 2 groove harmonic balancer, I run only one belt from the alternator over the water pump pulley down to the inboard groove. I run the compressor off the front groove of the balancer.
I've noted with a couple other project trucks that pulley alignment is critical, especially when you're trying to run 2 off of one belt. I found that using the "Gatorback" belts minimized the wear and tear. They seem to be a whole lot less likely to stretch and run quieter. If you're running a big alternator you might find they would be worth the extra money.
Dave
