This package includes a pair of 10 rib pulleys for the supercharger and the jackshaft that give a total of 15% overdrive for the supercharger. A premium quality 10 rib SC belt is included as well as a pair of the stiffer tensioner springs.
This billet aluminum crank pulley is significantly lighter than the stock steel crank pulley and best of all...it allows for another 10% of overdrive on the supercharger without worrying about belt slippage. Typically adds 3 to 4 psi of boost.