I think statments towards the Cherokee box being a better match than the 3rd gen box refer to swapping in a early A-body. The data in two of the threads John listed, support this. An A-body better matches a Monte SS, Buick GN, or a Cop Caprice. But those are not easy to find compared to a Cherokee. If you used a 3rd Gen F on an A-body, you would hit the stops prematurely, thus affecting your turning radius. Any of the above would work fine on our Birds. Depends on what kind of effort you are looking for.

I actually found a B-body Cop box first. Since I wanted to try more effort, and it would work on my friends A-body, I bought a Iroc box off of eBay and sold him the cop box for the same price. In reality my box cost even less than $60 (unless of course you count my time). The cop box was pretty cheap because instead of it being off a "Camaro" it was of an "old Caprice" (did I forget to mention it was a BC1?) The second yard was more into shredding then worrying about selling parts, so the 14:1 box was pretty cheap too.

I also picked up a 3rd gen wing with brakelight which mocked up pretty good fit-wise. But I'm saving that project for repaint time.