Does my truck have a torsion lift
 

I sold the lightning and picked up an 04 z71. I was reading about torsion lifts on these trucks and I hear that to fit 285-75-16's I need to crank the torsions. Well got some yokohoma grabber 285-75-16's on it with no rubbing so far (came that way). It doesn't look level though. Sorry don't know much about these trucks yet.

If you go under your truck and look at where the long bar that comes off your lower control arms meet just under the cab, and there should be 2 bolts that go up into that cross member, if they are all the way in, then they're cranked, if not then you could crank them to level the truck but be sure to measure the fender height before and after and adjust them accordingly.

on stock wheels your yokos should clear without cranking as long as theres no sag in the stock bars so it is possible that it is not caranked but as stated above take look for yourself

before you start cranking the bolt make sure you jack up the front of the truck. Don't crank the bolt when it's under load. Sure it'll work the first few times, but you'll grind down the bolt and sooner than later it won't sit correctly in the torsion key and it WILL slide out. I've seen it happen more often than i'd like.