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 and allow the re-use of existing serpentine belts.. All BBK Performance parts are backed by a 1-YEAR manufacturer’s warranty from the original date of purchase. An optional extended warranty is also available - giving you an additional 2 or 3 years from original date of purchase. Costs for the extended warranty option can be viewed when the item is added to your cart. The manufacturer’s warranty is based on normal use and installation of each product.. Power-Plus Series® Underdrive Pulley System; CNC Machined Billet Alum.; 3 Piece Kit; Incl. 8 Rib Crank Pulley/Water Pump Pulley/Alternator Pulley; Incl. All Required Hardware;. Lightweight CNC Billet Aluminum Construction -Retains Proper Cooling and Charging - Re-Uses Factory Length Belt. BBK 97-04 Ford F150 Expedition 4.6 5.4 Underdrive Pulley Kit - Lightweight CNC Billet Aluminum (3pc). 1997-2004 FORD 4.6L/5.4L F-SERIES/EXPED 3 PC PERFORMANCE UNDER DRIVE PULLEY KIT (BILLET ALUMINUM). 1997-2004 FORD 4.6L/5.4L F-SERIES/EXPED 3 PC UNDER DRIVE PULLEY KIT (ALUMINUM). Power-Plus Series® Underdrive Pulley System. Designed and Manufactured in USA. Engine Under Drive Pulley Kit. BBK Under Drive Pulleys. Under Drive Pulleys. Pulley Kit

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