This Uniball Upper Control Arm system for the Sierra and Silverado provides a 3.5in increased ride height over stock without creating suspension bind at full droop. The 3.5in lift is accomplished with steel spacers that utilize the factory coilover shocks for a smooth ride. Uniball Upper Control Arms (UCA). The heavy duty Uniball Upper Control Arms are constructed of the finest material with .120in wall 1.50in OD 4130 Chromoly tubing. High quality 1in FK Stainless PTFE lined Uniball bearings are used in place of ball joints. These super stout Control Arms are designed for increased longevity in rugged offroad conditions while providing a more positive on road feel. Rear Lift. The rear lift for this system comes from 1.5in blocks and u-bolts paired with our Stealth shocks. Features Increased ground clearance. Uniball Upper Control Arms. Increased fender clearance compared to a Leveling Kit for 33in tall tires. Suspension can be restored to stock. Easy installation.