Think about this, the RRC used a single 13mm belt to drive the PAS pump, which had a twin pulley, this in turn runs the alternator via a second belt. The wate rpump/air conn is the same. There are 4 belts in turn.
If you source the PAS pump from a V8 you might then be able to space the alternator forwards and use the twin pulley in the same way. Also because the alternator pulls to the opposite side than the crank there is less side-load on the PAS pump puller/bearings & bracket. With a bit of fabricating you should be able to fatsen it to 3 or 4 fairly humble looking fixings on the engine.
