Huge difference between the two. 78-79 are fullwidth, high-pinion and have cast-in radius arm mounts (which won't lend themselves to leaf springs). 77 and earlier are narrower, low pinion, have small U-joints, and I seem to remember something about smaller bearings. The F-150s are a bit different. The 78-79 are just like the Bronco, but 77 and earlier are fullwidth with welded-on radius arm mounts.
What I recommend looking for are the 8-lug axles from a 77-79 3/4 ton Ford truck (some of the newer years will also work, but a lot of the in-between years have TTB craziness). They are already leaf sprung, the front is a high pinion Dana 44 and the rear will be a Dana 60. Lots of years of fords, chevys and dodges used similar dana 60 rear axles so you don't necessarily need to find a matched pair.