March Pulley Sets are precision CNC machined from 6061-T6 aluminum for extra strength, durability and trueness. Finished with a ''No Polishing'' clear powdercoat. Early model Chrysler engines are easily converted from the old low performance V-belts to smooth operating 1'' wide serpentine belts while retaining the standard rotation water pump. Later model engines that already have a serpentine belt system will benefit from March Performance pulleys by reducing accessory drag which will increase horsepower.