'04 F-150 help

About a month ago my dad bought me a 2004 F-150 crewbab FX4. I want to get some bigger tires than the 275's that came on it. I want to fit some 285's but i dont think I will have enough room to clear them without some rubbing. My friend told me to raise the torsion(sp) bars on it and i dont know how to do this. Could someone tell me how to do this and how much i need to raise it. Any help would be appreciated.

on a new f-150, i'd prolly rather not mess with torsion bars without someone who knows exactly what theyre doing with you. Now if you want alittle bit a lift, try to find some coil spacers, they normally run about 10 bucks but there rubber spacers that go under your coils.