I did the 4wd conversion on my 96 F150 last spring. Everything bolts right in with ZERO drilling, cutting or welding. You may have to cut out the trans tunnel on your 80 because it was an automatic 2wd, that's easy Ford dimpled the area that needs to be cut out. I had to drill 3 holes on my truck only because I installed a 2.5" suspension lift (had it laying around from another project) along with the conversion. As previously stated the 2wd rear springs are narrower (2.5" wide) than the 4wd springs (3" wide), I am still running the 2wd springs with no issues, I added the factory block that stock 4x4s run. Everything up front is all pretty much interchangeable: Coil spring buckets, coil springs, TTB/TIB brackets, radius arm brackets, steering linkage... you more than likely need longer front shocks. Pedal assemblies will interchange, I would suggest going with the newer hydraulic clutch set up... it seems to work better. The 4x4 trans crossmember bolts right in the same place as the 4x2.