Hey BigMike,
The Serpentine pulley part number from Kenworth is #KA1480 Its a 6 groove setup though where if i remember correctly the AC on a 3rz has only 4 grooves. Though I would guess you could probably get away running a 4 groove belt on a 6 groove pulley.. Sure would be better then welding on the v-groove and having it balanced like you were saying..
As for the compressor, its flat out awesome!! There just isn't anything that I've aired up next to that out do the RV2!! Its sweet and a whole lot more original then the old York thats so common now!
Anyways, this is my setup during its infancy...
Just let me know if you need any info.. I remember when I was in the research phase and coming up empty....