Ford Repair: engine compatability, salvage yard, blown engine

Question
I have a 1998 ford expedition 8cyl i believe its a 5.4 with a blown engine and bought a 2000 expedition engine of the same size and had it installed by a mechanic but he couldn't get it running, i didn't get the brain for the new one and was hoping if the 2 were actually compatible and what i would need if they were(just the newer computer? or more)"

Answer
i would think they should have been interchangeable but you should be able to check with a salvage yard most better ones have software that tells them what is interchangeable i don't swap a lot of used engines for the reason you are talking about i have seen my share of ones that weren't compatable after the fact.