Here is a direct bolt on upgrade for anyone with a stock to a 3.5" lifted 2005+ Superduty. These heavy duty fabricated radius arms are designed with a fixed castor setting designed to increase castor 1.5* over stock on a truck with a 2.5" lift. These are CNC formed from laser cut 3/16" steel with additional internal gusseting to ensure they do not flex like stock arms. These use and come with an OEM Ford radius arm bushing at the frame side. We have offset the arms away from the tire to allow maximum clearance for larger tire combos. As well, they tuck up as much as possible for maximum ground clearance!