ChevyMan_AL

I just recently purchased a 96 Z71. It has a brand new 5.7 crate and a newly rebuilt transmission. I have also put new brakes, calipers, rotors, and redone the drums on the back. When I bought the truck I noticed about 10 degrees worth of play in the steering. I thought this could be attributed to the new tires the previous owner had out on. 20" GMC Denali Rims and P255/75/R20 Bridgestone Duelers. I had the front end aligned and that corrected the drift in the ride but the steering is still loose. I have jacked it up and tested the linkage and there is no popping sounds coming from the linkage....what else could it be. I know it has a steering gear box, could this be the culprit or the power steering. If so is it easy to replace or need a mechanic? Thanks for the help on this!