This 8" diameter 10% overdrive balancer replaces the 7.25" balancer (crank pulley) normally on your centrifugal blower, (Paxton or Procharger)
It can also be used with a positive displacement / roots blower such as the Magnuson. The larger diameter drives your blower faster and significantly reduces slip and allows an increase in boost by 2-3 pounds while retaining the same size blower pulley.