1999-2007 Chevrolet Silverado 1500 2WD GMC Sierra 3" FRONT AND 1.5" REAR KIT FITMENT Chevrolet 1999-2006 Silverado 1500 6 lug 2WD; 2007 fits 'Classic' onlyGM 1999-2006 Sierra 1500 6 lug 2WD; 2007 fits 'Classic' only TECHNICAL NOTES Front suspension lift does not occur in a 1:1 ratio with spacer thickness Spring compressor may be needed for installation An Alignment is Recommended After Install Kit Contents 2x Steel Spring Spacers 2x Tapered Rear Lift Blocks 4x Extended Square U BoltsInstallation Instructions U Bolt Specs Square 10" Long x 2.5" Wide x 9/16 Thread Pitch American Automotive u bolts are made of cold drawn certified 1541 carbon steel OEM factory material with grade 8 hardware. Lift Block Specs Tapered 5" Long x 2.5" Wide x 1.5" Tall American Automotive steel lift blocks are made from 1/4" carbon steel which is stronger than aluminum. They are designed to increase rear load and towing capacity. American blocks absorb noise and vibrations, and are tapered for perfect pinion alignment. Road Fury high-performance suspension lifts by American Automotive are made of US carbon steel. Higher-quality, more expensive laser cuts and produce stronger, better fitting and more impressive looking lifts. Road Fury gives your truck a more imposing stance and the extra clearance needed to fit larger tires and custom wheels. You will be proud to install our product on your vehicle and once installed, our product will outlast your truck. All Road Fury bolt-on product works with stock suspension and is easy to install. Prime mill certified and heat treated, our material is tougher than Chinese aluminum, cast, polyurethane, imitation alloy and other steel product. We pride ourselves on our product, especially our performance series, and so will you.