35/12.5/20

what kind of lift does a 2004 f150 4x4 need to house those?

Iv got 17x10(trucks lifted about 5-6") on there now with 34.36/12.40/17" (converted from 315/70/17)

I have no issues with the setup I have stated above, but with the setup im asking about, would I have issues?

 

Tire height and diameter should be close to the 17's, they ought to clear unless they are a mud tire with large side lugs.

 

they should clear np if uve already got a 6" lift

 

RIght, a 315/70-17 is basically a 35x12.50 tire (tire sizes are rounded up to the next whole number). The wheel size doesn't matter in fitment. A 35x12.50 is the same size tire whether you use a 17 or a 24 inch wheel. You just need to pay attention to the wheel width and backspacing.