I've done an '01 Mustang 8.8 to an '86 Camaro, and I've done the Explorer 8.8 to an '86 S-10. The Explorer housing is at least 50# heavier, and for what? Guys push stock-housing, un-trussed Mustang housings into the 9s at the dragstrip in 3000# cars, way heavier than any t bucket. The Explorer outer bearings, and therefore the shafts also, are also larger and heavier than necessary. You don't need the Explorer housing to run 31-spline shafts of you need 31s, Mustang guys order 31s, 33s, and even 35s all the time, tho many do run 9s on stock 28s.
I suggest you sell yours and get something lighter, like the Ranger version. The 4.10 gears are excessive for anything but a T56 with the 0.50:1 sixth, anyway.
I managed Rome Driveshaft in Georgia for a year, that 1.25"/15" is fine for cruising, not for racing.
I appreciate the detailed feedback... I've been hunting for a suitable rear end for several months. What drew me to the explorer was the fact that most were limited slip with disc brakes, the lug pattern works with my current 14" wide wheels and there was minimal detail work needed to strip off the existing mounts. Rangers were all drum brakes and I don't recall seeing any of them with posi. Most of the mustangs that I found with limited slip were four lug for whatever reason and needed some serious surgery to get the spring perches off "cleanly", not to mention the big "horns" on the top of the center section that would have to come off to accommodate the panhard bar.
The Explorer's right side is also the perfect length (with the pinion centered) for my current 15.5X29's and wheel offset that will put the tire about an inch from the bed, VS the massive (IMO) 6" gap that I currently have with the 10 bolt (2.43 gear) Camaro unit that's in it today.
This thing never sees the freeway or any kind of "touring", so while a 3.73 would have been preferred, the 4.11 didn't scare me off. I have more shows & events within 10 miles of my house than I can even count, so the shorter gear doesn't concern me too much. It spends all of it's time here in town. I think the biggest problem will be not blowing the tires off leaving a stoplight!
While the extra 50lbs of unsprung weight isn't ideal, I think it's a fair trade off for the ease of installation.