I currently have 17 stocks with what seems to be a lowerd suspension...I'm not sure how low I am but it has a nice stance. I want to put some 15's or 16's in the back with some drag tires...but I was wondering what the widest wheel I can go with? Also what rims would you guys recommend? Thanks

 

You can run a 275 out back on a 9.5" wheel with an offset in the 50-55 range, which is about 7.5" backspacing. For my drag setup, I run a set of C4 corvette ZR-1 fronts, which are 17x9.5, 56 offset and they fit perfectly with a 275 MT drag radial. There are some 16" f-body wheels that will work. If you want to go 15, Weld has some nice options.

 

Will I need to do some fender work? Or will they fit right on? Also will I have any issues fitting the 15's on the rear? Won't have any clearance issues with the brakes or calipers?

 

With the 275/50/15 you will need to roll the inner fenders.. I had Bogarts on my Goat I didn't need to mess with the brakes at all.... Probably will depend on the brand of wheel...

 

What if I'd go with a 265? Would I still need to do some fender rolling?

 

The GTO squats a lot. I f you run a taller tire than stock you will have to roll fenders. What are you wanting to accomplish with a 15" rim/tire combo? If u have someone that knows how to roll the inner fenders you will never know its been done.. Not really going to hurt anything..
I had air bags and QA1's on my car on the rear. You can adjust air pressure and adjust shocks to keep the ride quality just at the track you wanna stiffen it up a bit to keep from squatting so much... Also helps eliminate wheel hop.

 

I just want to have a setup for the weekends..something I can switch on and off from my stock wheels.

 

I would just find a nice set of 17/18's for cruising... You can find some pretty nice wheels with a lil lip in the rear.. I thought you were wanting a race setup...

 

To get any decent tire width you need to roll the fenders and maybe even massage the inner fender a bit. Wheel offset (the rim is the edge of the wheel) and width affect tire size a lot. I got 285s on stock 17"s widened to 9". That makes about a 56mm offset. I can squat to the bump stops without rub.

One little additional tweak that eliminated any contact was replacing the inner and outer control arm bushings with poly. The rear control arm "fork" is what the wheel spindle is attached to and it's held in position and pivots on those two points. Excessive play from the soft, void filled rubber bushings can cause the control arm to move outside of its intended arc. They also help keep your wheel camber in spec so you have good tire patch contact with the road and good tire wear.

 

Awesome advice as well!!!!

 

Agree either Svede with regard to bushes.

I drive on 19" x 9.5" with 275/30/19 on the street and race on the factory 18" x 8" with 265/40/18 drag radials.

 

26-10-15 or 275-50-15 on a 10inch rim with 7.5 backspace works nice.