need help with wide tire setup (rear)
 

First off the car is an 83 gt t-top with a 347 and roll bar and all the goodies to go with that kind of setup.
I want to go with about a 10-12 inch wide tire(10-12 inch wide wheel also) in the rear that isnt too tall
(about 26 inches).
The thing is, I know nothing about tire sizing, (i.e. 275/60/15),other than the 15 means the wheel sizing. I need to know about backspacing and anything else that can help me out.
Heres the final product I want to end up with. Im going for an old school muscle look that includes corvette style 3 inch glasspack side dumps with heat shield, a jacked up rear end (raised not really jacked), and a wide wheel and tire combo that isnt too tall that kinda gives the whole wheel a kinda cube shape. I want the wheel and tire to stick about an inch or two out past the fender which is where the backspacing and jacking up the car would prevent rubbing right and give me the look right?
Is this possible?
How do you lift the rear end of a fox body?
Any help would be appreciated, I am doing this for looks not performance, I think it would look awesome,
thanks.

Re: need help with wide tire setup (rear)
 

please god do NOT put sidepipes on a mustang!

about the wheels, i use a 275/60-15 MT DR on a 15x8" wheel (would be better on a 15x9) with 5.5" backspacing

Re: need help with wide tire setup (rear)
 

fiveoh patrol is right...please don't put glasspacks and or side exhaust on a fox. as far as tire sizing, my take is... take a 275/40-17 as an example. 275 is the tread width in millimeters. 40 is the percentage of the sidewall compared to the width of the tire from sidewall to sidewall (not tread width). (so in the case of our example tire, the side wall width would be 40% of the width from sidewall to sidewall (which is just slightly more than the tread width). of course 17 is the rim size (diameter in inches). don't know what would be good for the look you are going for, but don't stick the rear tire too much from the fender or (i think that looks like crap). to me the widest you can go while still fitting inside the fender well, or just outside looks best.