I have a Reichard Racing ultra-grip pulley. It's a great peice no slip even when I had the "stock" vortech kit belt made for a pulley 1/3" longer... I did however just shred a belt, but amazingly the only pulley it DIDNT slip off of was the blower pulley hah! Call Modular Powerhouse and they will hook you up with whatever you want, pulley from paxton or RR pulley.
To put mine on my vortech I left the blower on the car, took the inlet off (power pipe in my case) and put a wrench on the nuts that hold the impeller in place, this allowed me to wrench on the bolt that holds the pulley onto the blower without it spinning. Impacting would work...but just like a crank pulley, head stud, etc., I wouldn't use an impact for fear of breaking something sensitive.