The Explorer rear end has a lot of pinion offset. The FOX Mustang 8.8 is about 59 1/2 inches wide over all and has the pinion more centered. These are getting easier to find and all of them had the Trac Lock differential. You might have to put new clutches in it. They are 4 lug, but 5 lug axles are not very expensive and you can use Ranger drums with the 5 lug axles.
Most S trucks had the 7.5 rear end. In '90 they got an axle upgrade from 26 spline to 28 spline. The 8.5 rear ends in the S trucks had 30 spline axles. All of the truck limited slip differentials are Governor Lock, which is not a good choice for a performance application. The 2 WD S truck rear end is pretty narrow. The 4 WD rear ends are 4 to 6 inches wider than the 2 WD.