1979-93 Ford Mustang 5.0 Billet Aluminum Serpentine Pulley & Bracket Kit - Machined 1979-93 Ford Mustang 5.0L Underdrive Pulley Kit with all the Brackets. Comes Complete with all Hardware. Machined billet aluminum 6 groove serpentine alternator, crank, power steering and water pump pulley kit, power steering bracket kit, and alternator bracket kit. This kit is CNC-machined from the most durable materials possible: 6061-T6 billet aluminum. Typically, a set of CFR pulleys will increase horsepower by 11-15, and increase mileage by 2 to 3 MPG.