The March Performance serpentine conversion pulley kit feature simple-to-bolt- on pulleys that replace your low-performance V-belt pulleys, while retaining your standard rotation water pump. They are CNC-machined from solid billet 6061-T6 aluminum for extra strength and wear, and are covered with a no-polish clear powder coated finish. Performance series pulleys create approximately 12.5-15 hp at the rear wheels by reducing accessory drag. They also eliminate belt throwing and are designed for normal street driving.