ADD 8-13HP! MADE HERE IN THE USA!!!!!! ADD THROTTLE RESPONSE TO YOUR SRT10 VIPER WITH A NEW JTSVP T6061 BILLET UNDERDRIVE PULLEY! We machine our pullies in house from T6061 billet aluminum, dropping from the oem diameter pulley to our underdrive pulley slows down the accessories, thus adding free hp and dropping your quarter mile times! During testing, we have seen on average 10rwhp, and a tenth or two quicker in quarter mile acceleration. The underdrive pulley was designed and tested to not have any effects on accessories such as the alternator or a/c. The JTSVP pulley IS A ONE PIECE PULLEY Our billet underdirve pulley comes with new bolts and serpentine belt. SO ADD YOU HP TODAY THE EASY WAY!  They come semi polished.