Ford changed the platform for the 80's and the frame and steering is inferior to the earlier trucks.
(look how many 78 ford trucks are still on the road versus 81's)
If I was to build a Ford truck now, I would look for a 74 or 75 3/4 ton.
Good truck with excellent transfer case and diff's.
(I am a Chevy guy mostly, I'm sure there are Ford guys could tell you better.)