March Power and Amp underdrive pulleys increase engine horsepower by reducing the amount of power required to drive external engine accessories.

Underdrive pulleys, 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 March pulleys will increase horsepower by 12-15, resulting in quarter mile time improvement of .2-.25 seconds. All pulleys are manufactured from Billet Steel or Aluminum, exceeding factory quality.