for 4.8,5.3,6.0 and 6.2 engines

UPD Performance 25% Underdrive pulley 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 heavy cast iron crank pulley with a lighter CNC machined underdrive pulley, the accessories are slowed, resulting in more horsepower available to the drive wheels. Typically, a set of UPD 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 and reducing the factory balancer inertia with a precission machined and balanced USA made crank balancer.

Balancer is special nitride coated and not painted like most.