[quote][/quote]Hey guys, just picked an1986 Monte SS that I inherited from my dad . I purchased a set of wheels in 18x8 with 0 offset for the front . 18 x 9.5 +6 offset for the rear. I was told it was a direct fit from the dealer. I went to bolt them on and the rear bottoms out on the frame. I wrote the manufacturer’s and still haven’t heard back. Also the front looks pretty close to the sway bar. Any ideas on spacers ? Or should I just get a different offset? . Any help is appreciated.

I would measure and possibly do a rear frame notch on the rear. How much tie rod clearance do you have?

Did you use the wheel fitment guides down in the rolling chassis link?
http://www.montecarloss.com/community/ubbthreads.php?ubb=showflat&Number=325469#Post325469

Those offsets should be pretty darn close. I run 9.5" wheels with 5" backspacing, which works out to about +12mm offset. Do they bottom out on both sides or just one? It is close, but it has to be close to fit a 9.5 and not have it stick out past the fenders. Worn trailing arm bushings, or possibly an accident bending the frame, can cause the rails to not be centered over the axle. This can be remedied with adjustable upper trailing arms if that's the case.

First thing I would do is get a tape measure and a straight edge and verify the wheels are indeed 9.5" wide. This is measured from where the tire bead contacts the rim on the *inside* of the lip. You'll have to measure outside the lip and subtract off about 1/2", depending on the rim design.

Then verify that they are +6mm offset (measure backspacing and convert).

If that is correct, I would try both sides on and that will tell you if the axle is centered.