Install a set of BBK performance underdrive pulleys and see an average of 8-15 additional horsepower over the stock pulleys. Under drive pulleys increase engine output by reducing the draw of the engines accessories by slowing them down and reducing the HP they use. Additional and significant performance improvements can be seen by reducing the weight of the pulley versus the original pulley which is why we recommend the BBK CNC Machined billet aluminum pulley kits for maximum horsepower gains. ALL BBK pulley kits are designed as direct bolt on replacements for the current factory pulleys and retain full cooling and charging characteristics. BBK under drive pulley kits are vehicle specific and each kit comes with complete installation instructions. Requires the use of a NEW Serpentine Belt - 6 Rib - 91.5 in. Power-Plus Series? Underdrive Pulley System; CNC Machined Billet Aluminum; 3 Piece Kit; Incl. Crank Pulley/Water Pump Pulley/Alternator Pulley/All Required Hardware; Chevrolet: Blazer 88 - 95 Base / Cheyenne / Deluxe / LT / Scottsdale / Silverado / Silverado Sport, Chevrolet: C1500 88 - 95 Base / Cheyenne / Scottsdale / Silverado / WT, Chevrolet: C1500 Suburban 92 - 95 Base / LS / LT / Silverado, Chevrolet: C2500 88 - 95 400 SS / 60th Anniversary / Base / Cheyenne / Custom / Scottsdale / Silverado / WT, Chevrolet: C2500 Suburban 92 - 95 Base / LS / LT / Silverado, Chevrolet: C3500 88 - 95 Base / Cheyenne / Scottsdale / Silverado, Chevrolet: K1500 88 - 95 Base / Cheyenne / Scottsdale / Silverado / Sport / WT, Chevrolet: K1500 Suburban 92 - 95 Base / LS / LT / Silverado, Chevrolet: K2500 88 - 95 Base / Cheyenne / Scottsdale / Silverado / WT, Chevrolet: K2500 Suburban 92 - 95 Base / LS / LT / Silverado, Chevrolet: K3500 89 - 95 Base / Cheyenne / Scottsdale / Silverado, Chevrolet: R1500 Suburban 89 - 91 Scottsdale / Silverado, Chevrolet: R20 88 - 88 Cheyenne / Custom Deluxe / Scottsdale / Silverado, Chevrolet: R20 Suburban 88 - 88 Scottsdale / Silverado, Chevrolet: R2500 89 - 89 Silverado, Chevrolet: R2500 Suburban 89 - 91 Scottsdale / Silverado, Chevrolet: S10 88 - 95 Baja / Base / Durango / EL / LS / SS / Sport / Tahoe / ZR2, Chevrolet: S10 Blazer 88 - 94 Base / High Country / LT / Sport / Tahoe / Tahoe LT, Chevrolet: Silverado 95 - 95 SLE / SLX, Chevrolet: Suburban 88 - 94 Base, Chevrolet: Suburban 1500 95 - 95 Cheyenne / Custom, Chevrolet: Tahoe 95 - 95 Base / LS / LT, GMC: C1500 88 - 95 Sierra / Sierra SL / Sierra SLE / Sierra SLT / Sierra SLX / Sierra Special, GMC: C2500 88 - 95 Sierra / Sierra SL / Sierra SLE / Sierra SLT / Sierra SLX, GMC: C3500 88 - 95 Sierra / Sierra SL / Sierra SLE / Sierra SLT / Sierra SLX, GMC: K1500 88 - 95 Sierra / Sierra SL / Sierra SLE / Sierra SLS / Sierra SLT / Sierra SLX / Sierra Special / Sierra Sport, GMC: K2500 88 - 95 Sierra / Sierra SL / Sierra SLE / Sierra SLT / Sierra SLX, GMC: K3500 89 - 95 Sierra / Sierra SL / Sierra SLE / Sierra SLT / Sierra SLX