It is most certainly the rears you have to worry about. as well as the front, your 8.5 fronts did not work because you had a higher offset than you needed to have. many people have run 8.5's in fronts with no problems they just had the correct offsets. The rears you are posting, abe, would not work with that width. it would sit too far in, probably hitting suspension components. the stock rear wheel is +22 on a 9 inch rim. the higher the offest the more it sits inside the wheelwell. the lower the more it "pushes" it out. the offset is how far it sits from the centerline of the wheel. like bmorgan said use the fitment calculator.