This auction is for a 2.90" 8 rib PULLEY for VORTECH will also fit  POWERDYNE, SCORPION with 20mm (.788") shaft size.  

(One end has 0.30" boss/standoff, and Other end has 0.10" boss/standoff from flush - can also machine to suit)

These fit POWERDYNE XB-1A, BD-550, BD-600, BD-10, BD-11, BD-11A,  Cool Charger, Ford Motorsport, O2 Force BD-100, and B&M BD-12, SCORPION XB-1A, VORTECH V-1, V-2, V-3, V-4, V-5, V-7, V-9, etc. superchargers input shafts.