I just swapped from the V belts to a Serpentine setup on my '65..
I've got the Borgeson power steering kit with their saginaw pump, a 1 wire alternator, Sanden AC compressor and standard rotation pax side exit water pump on a '65 timing cover.
I had originally run a 3g alternator, but the cases have so much variety that I found it easier to grab a tuff stuff 1 wire for the new setup. Instead of shimming/cutting etc, it bolted right up.
March makes nice stuff, but holy smokes it's pricey. I decided after much research to run CVF racings setup. In black. Its very nice. They were great to deal with and took many phone calls while I was sorting everything out. Shipping quick and the instructions decent. It lines up nicely and is pretty easy to adjust.
I did run into one problem. There are TWO different setups for the saginaw pumps. Plus two pumps, one with Press kit pulley and one that uses a keyway and bolt. Borgeson had sent me (three years ago now) the pump with a press fit and the wrong bolt pattern. I had always wondered why, even with their brackets why it never quite sat right with the v belts. Found out with CVF's kit that it was indeed way wrong. A bunch of digging online, a few phone calls I finally had it figured out and verified with a trip to the local speed shop and got myself the proper pump from Tuff Stuff. Pretty much everyone that runs the saginaw in hot rod/classic applications recommends the keyway (bolt on) pulley. I'm just waiting on the pulley to ship here to Canada from CVF and it'll be good to go.
I fought belt squeal on the alternator for a long while. Thats one of the many reasons I went serpentine. Maybe post a picture? I too had difficulty tensioning the PS pump pulley with the v belt and the Borgeson pump.
I used a March Pulley kit (not sure the part #). The biggest problem I ran into was finding the right pulley to replace on the Borgeson...I eventually found the correct one through Billet Specialties. I attached pics