I just bought a 89 F-150 5.0L, 5spd, 4x4, reg cab long box, but i'm not sure if it has a suspension lift front and back i have a couple of pictures if anyone can tell me, the rear also has firestone air bags, and also if anyone knows if i can run 31x10.5x15 tires without rubbing thanks!!!

 

I don't think the truck is lifted. You shouldn't have any issues running of those tires. I ran 33X12.5X15's on a stock 83, and had no issues. The only thing I can remember on the 89 is maybe the back side of the bumper and valence may rub. A buddy just trimmed this area away.