Hello everyone, I recently posted a thread in the monte section about some rear axle options I had. Well I have decided to go with a 12 bolt so I looked further into the 12 bolt my dads had stashed away for years. Its from a 1972 pontaic gto, its posi, with 4.11 gears. It needs some work because its been sitting in a shed for over 20 years. So I have a few concerns: What is the width of the gto 12 bolt and how much wider is it than my stock 7.5"? What backspacing will I need to keep the tires tucked under the wheel wells? I plan on running 15" wheels and tires for now, so whats the widest rear tires that might fit under the car with the 12 bolt? And what would everyone do to prep a rear end thats been sitting unused for 20 years to be bolted into my monte? Any help or advice would be great, thanks!