These two ProCharger superchargers use a slightly larger, 9.75-inch volute for higher airflow and HP ratings and retain all the design advantages of the other F-Series models. Want to turn it up on the weekends? No problem. With a wide range of pulley sizes available you can quickly change boost levels to suit your needs. The mounting brackets, like the transmission case, are constructed from 6061 billet, providing a solid foundation for your ProCharger. The drive system utilizes a 12-rib belt (cog option available) with a rugged spring loaded belt tensioner and oversized pulleys that provide maximum belt contact for peak power output. These kits also include a standard carb bonnet and the tubing required to boost your Holley 4150-style carburetor. The F-1 thru F-1R utilize an advanced helixed impeller capable of accommodating a broad range of applications. The F-1 flows enough air to feed 1050 hp while the F-1R will support up to 1,200 hp.