There are 2 major differences on the 3.7 that will not let them interchange. The 1st and most important is the number of teeth on the crankshaft tone wheel and number of notches in the right cam sprocket.This is for the Cam and Crank sensors to read so the engine will fire and actuate the injectors. There are 2 different types. The earlier style uses a JTEC controller and the later uses a NGC controller. I am not sure which one you have but you must use the same kind that you have for the engine to run.
The other issue is wether or not your engine has EGR or not. You cannot use a non EGR engine in a vehicle equipped with EGR. However you can use a EGR equipped engine in a non-EGR equipped vehicle if If you block or plug the EGR plug on the rear of the left cylinder head. Other than that you may have to change the intake and or exhaust manifolds and possibly the oil pan/pick-up tube to complete the swap. No biggie. Hope this helps.