i love Bronco IIs. the explorer is the evolution of the B2. They are all in the RBV (ranger based vehicle) family and most parts are relatively easily swapped. The bronco IIs come with 7.5 rear and dana 28 front axles but the newer ranger stuff can be retrofitted into the older B2s. 8.8 and Dana 35 ttbs are nearly bolt in. So is the 4.0L.
for that matter a 5.0L 302 swap is fairly straight forward as well. If you wanna go solid axle, the jeep axles will go in with little fabrication and so will the early bronco (66-77) front axle.
There is a world of information out there on
www.therangerstation.com its a group of wheelers from all over the country who come together much like this place and share knowledge, except over there they are all driving RBVs.
B2s are cheap and easy to find craigslist. there is a junkyard between asheboro and lexington that specialized in RBVs, back when i was into that thats where i got all my spare parts from.