You'll need the wiring harness and the computer from the 4.0 engine. Google therangerstation forum and you'll be able to search the forum for details on how to do this pretty easy swap. There have been several people who have swapped engines like this into their rangers.

They are identical engines. You should not need anythng

why not trade trucks sounds way easier

Are you from New Orleans ?

I have a 1994 ranger with the 4.0 in it with an auto transmission. It has almost 200k miles and just blew a head gasket. My pawpaw has a 1998 explorer with a 4.0 sohc in it and I was thinking about taking that engine out and using it in my truck since my engine has so many miles already. What all will I need to do for the swap? Thanks!