Underdrive pulley systems increase engine horsepower by reducing the amount of power required to drive external engine accessories. For example, the alternator, power steering, water pump and air compressor rob horsepower from the engine. By replacing factory-sized crank and accessory drive pulleys with a resized pulley, the accessories are slowed, resulting in more horsepower available to the drive wheels. Typically, a set of Auto Specialties street pulleys will increase horsepower by 12-15, and increase mileage by 2 to 3 MPG. All pulleys are manufactured from Billet Steel or Aluminum, exceeding factory quality.
- Requires Shorter belt.*** Following are gates part numbers and are for vehicles equipped with A/C And Smog "or equivalent eliminator pulleys"
- 4-5/8" - Pulley Diameter
ASP - Quality. Performance. Products.
ASP is one of the industry's leading producers of Mustang performance pulleys. Since 1988 ASP has been machining underdrive pulleys in house to give you the most performance for your Mustang. Each pulley goes through a CNC lathe for accurate measuring and cutting. The pulleys go through 2 cycles and a quality check to ensure each part is perfect before it leaves out of the door.