Lifting an 80 series introduces pinion angle changes. Addressing these situations is critical. Lifting an 80 series in the rear with out changing the pinion angle can introduce unwanted vibrations. These Arms will allow you you adjust the rear pinion angle downwards to re-create parallel pinion flange to transfer-case flange angle. These adjustable upper control arms can also help move the rear axle back up to 10mm if you are wanting to run a 35-37″ tire, centering the tire in the wheel well. NOTE. Longer Lower control arms will be required if you decide to move the axle rearward.