I am using my stock 305 pullies now with a 6-rib belt running the alternator and waterpump. I talked to a guy at ATI and he said I would have to convert to v-belt for my alternator and waterpump.

Does anybody know what pullies I should ask for to keep the 6-rib and be able to run the 12-rib for the supercharger?

I guess the issue is that I am trying to buy a supercharger for a big-block and trying to use pullies for a small-block, but I like running the alternator with a 6-rib.