i found a 90 ford ranger with a v6 fuel injected and standard 4spd i was wondering how difficult it would be to swap the engine and driveline into a 83 ranger carberated and automatic

 

Wouldn't be difficult to do the swap at all, the Ranger frame was the same from '83-'92, only thing that really changed was the nose, so as far as the mechanical part of it, no sweat(to me anyhow)....it's the wiring that'll get ya.......Not great fun but definitely do-able.
Scott
PS-except switching TO the 5spd, I've never done this, you'll have to take the pedals out of the 90 etc, not sure on that one! You may want to try and find an auto or see if the one in the old ranger works, I think it'll bolt up....