I have 295zr17's on the back with 2000SS Camaro wheels. I think they are 9" wheels. They have 2" spacers/adapters on them. I have about 1/2" clearance on the outside, and 3/4" in the inside. I haven't lowered it yet, or driven it so I don't know if it will rub yet. Pic at link below.
http://www.scarymaggot.com/itlbtu/PICT5634.JPG