if your gonna lift it and your worried about MPG, dont lift it.
as far as i know my friend with a 2wd 07 avalanche with a 6" procomp, 35" tires, and a 5.3 gets about 11-14 in the city and like 16 on the highway with stock gears. would probably be a bit better if he re-geared.
2007 NNBS CC 4.8L 325/60/20 Toyos on 10" Lift 4:10 gears and I average 15 mpg all around. If I cruise on the interstate I can get as high as 16.5mpg. I also have the Edge Evolution set on Economy. Dont think it helps much. I credit my mileage to being decent to my gears honestly. Its perfect to get up to acceleration and dont sacrafice many RPMS at highway speed.
A forum community dedicated to GMC and Chevy full size owners and enthusiasts. Come join the discussion about Silverados, Sierras, and other full size trucks performance, modifications, suspension, lift kits, tires, maintenance, and more!