the engine is a 1994 5.9 magnum 70,000miles

truck its going into is a 1991 D150 2wd A904 automatic.


what will i need to change to make this swap go smooth? The engine came with a flywheel with the weights so that problem is solved

 

This should work as the trans should be an RH not RE, aslong as you have the Powertrain Control Module (PCM). Transmission mount is different and further back with a shorter driveshaft required.
I would suggest getting wiring diagrams for both to compare hook up points.
I was assuming your swapping engine and trans, maybe I got this wrong. Are you hooking the 5.9 to the 904 3 speed?
If you are you'll need to notch the bellhousing for the crankshaft sensor.

 

its just a engine swap. keepin the 904. plus i'm going to buy the edelbrock magnum 4 barrel intake and put a holley on it. never liked fuel injection anyway. going to bessler's you pull and save saturday and buying all the front accessories, motor mounts, dizzy. anything else i should pick up?