Serpentine Pulley Set for Ford 5.0 Mustang 1979 to 1993 Polished Billet Aluminum

Polished billet aluminum 6 groove serpentine alternator, crank and water pump pulley set. The pulleys are CNC-machined from the lightest,most durable materials possible: 6061-T6 billet aluminum. Underdrive pulley systems increase engine horsepower by reducing the amount of power required to drive external engine accessories. By replacing factory-sized crank and accessory drive pulleys with re-sized pulleys, the accessories are slowed, resulting in more horsepower available to the drive wheels. Typically, a set of these pulleys will increase horsepower by 11 - 15, and increase gas mileage by 2 to 3 mpg. Specs: Crank = 4-3/4" Diameter = 21% smaller Water Pump = 5-1/8" Diameter = 8% bigger Alternator = 2-1/2" Diameter = 10% bigger GATES BELT K060900 FOR 87-93 5.0 MUSTANG WITH A/C