Rear diff track width?

How wide, drum to drum is the rear diff on an Aerostar? I was looking at a wrecked van my friend has as a possible donor for my Mercury Zephyr project, since these vans are a trailing arm/coil spring setup. I think the other question would be, what are the widths of the mounting points for the control arms and spring pockets? Just want to make sure it would be worth my time grabbing this diff.