This CNC-Series 5.5" billet aluminum power steering pump pulley is designed to work exclusively on Ford power steering pumps. Depending on the year and engine size, Ford offered 2 different diameter pulleys, a 5" and 5.5". Be sure to measure your original pulley to get the right diameter. They are interchangeable and both will work for just about any application. This larger diameter version is best suited for high RPM operation as it will help protect the pump. The smaller 5" version provides more power assist at low RPM especially idle but not ideal for racing or high RPMs.