I'm working on a 51 gmc 1/2 ton. Not much original at this point. I boxed the frame and installed a Mustang II front suspension. The front hub to hub width measured 57-5/8. I'm trying to determine what width the rear axle should be? I found a post referring to using a 62" axle. Does this sound right? I want to use a ford 8.8 or 9" with disc brakes. Any donor suggestions? Oh, and the specs show the wheel base at 116" but I understand the wheels won't be centered properly in the rear. Should I move it to 117?

Thanks