Fabtech?s 6" 4 Link Conversion system for the Ford F450 and F550 Super Duty is built to handle the on and offroad demands of the truck enthusiast. This vehicle?s suspension is more robust than the Ford F250 and F350 and therefore demands specialty parts only available from Fabtech. This system comes with everything needed to convert to a 4 Link front suspension. The system will provide less caster change throughout the travel range which benefits on road driving. Offroad the 4 Link system will provide more articulation than a Radius Arm for increased terrain traversing at all speeds. Fabtech?s 4 Link System has been proven in over 10 years of service in consumer, commercial and military applications. High quality components with properly design suspension geometry is the pinnacle of Super Duty suspension systems. Each Fabtech component is expertly built in house and has specific design features and benefits as listed below. FEATURES: LINK ARMS & BRACKETS - 2" OD Heavy wall link arms have 1/4" thick steel brackets at the axle with adjustable alignment cams and Fabtech?s legendary 5 Ton joints? to pivot at the frame for an extended service life. The 5 Ton joints? have been proven in military use for over 10 years and are quiet and strong. The 4 Link Arms attach to stout 1/4" thick steel frame brackets for a solid mounting of the new suspension. The geometry of the 4 Link arms and frame brackets has been designed to provide an improved highway ride due to reduced caster change and able to tackle rough offroad conditions better than a Radius Arm suspension. COIL SPRINGS - American made coil springs have been designed for a very compliant ride quality both on and offroad. Each coil is preset during the manufacturing process to insure no ride height settling over time. Allows for a 2" increase in wheel travel over stock when used with Fabtech shock absorbers. TRACK BAR BRACKET - 1/4" thick steel bracketry rep-ositions the factory track bar to center the axle under