Thrasher's press fit pulley R.A.T.'s removable pulley
Supercharger pulley: On all 97-00 Supercharged GTP's GM pressed the supercharger pulley onto the shaft so that people could not put a smaller pulley on to increase boost. There are 2 ways around this. First is Thrashers 3.5inch pulley that replaces the stock 3.8inch. Thrasher pulls your old pulley off the shaft and press's a new (picture notes the earlier gold pulley color, I have heard the new ones are factory black) one on. Second you could get a nosedrive assembly from Ram Air Technology. This replaces the whole nosedrive of the supercharger with a keyed shaft so once installed you can change the pulley size in a matter of minutes. It comes with a 3.6 or 3.4inch pulley to replace the stock 3.8inch. The Thrashers upgrade is $229.99 which includes a 3.5inch pulley and installation tool. The Ram Air Technology nosedrive upgrade is $278.00 plus installation with a $100.00 core charge, refundable upon return of core. Expect a 18HP increase with the Thrasher 3.5 pulley and a 15-22HP increase with the Ram Air Tech upgrade using a 3.6 or 3.4inch pulley.