Edelbrock Comkpetition 3.250in. pulley part #15850 allows you to fine tune the air flow and performance of your E-Force C7 Corvette or Enforcer Supercharger system to your preference. The Edelbrock #15850 features a 10-rib design for use with our E-Force street rod and muscle car Supercharger systems. Edelbrock Competition pulley part #15850 offers a Black Anodized finish.- 3.25in. 10-Rib E-Force S/C Pulley in Black Finish for Enforcer Systems