i would ask someone who deals with those laws before you did it. maybe because dakotas were once offered with a 5.2 you can still do it. swapping a 4.7 in place of a 3.9 is way to much trouble. transmission issues, bellhouse not the same.. etc. a 3.9-5.2 is pretty much a direct swap.

 

I don't see why the year of the engine would matter as long as you swap in the computer use something like 01 or so. That way you have the same setup for the comp and dash.