I know it has been done before and the mechanics I can deal with but I want to use the 5.9 fuel injected/automatic transmission complete power train. My questions are is there a way for me to use the computer system or do I need to find an aftermarket harness? I have both trucks and they are complete. Thanks for any and all input or any links to others that have made this swap.

IMHO your probably going about it the hard way by trying to merge the 94 chassis/frame and driveline INTO the 71, instead leave the 94 chassis and driveline alone, de-skin the required outer structures of the 94 and "hang" the 71 cab and front end sheetmetal on the de-skinned cut down 94, the bed is the easiest part to swap over, but by hanging the 71 sheetmetal on the cut down 94 cab and inner firewalls you can retain the majority of the 94 interior dash, steering and related underhood driveline and electrical systems, let's face it the 71 steering systems suck in function and design along with a lot of the other 71 driveline maladies

Mopar Muscle had an article a few years back where the owner dropped the body from a 71 or maybe earlier, but that body style, onto the chassis of a 94-01 4x4. Nearly everything lined up. Good looking ride too.

That is what I had planned. I would like to keep the fuel injection and serpentine setup so that the transmission works. I'm not opposed to a carb but I need everything to work

I think the interior of the 71' looks way better then the 94 by a long margin. Aside from re skinning the whole truck I've seen a few others where they cut the firewall from the newer vehicle and spliced it in which eliminates a whole lot of hassle in wiring.

Other wise there is magnummopar.com who will cut down the wire harness from the 94 to the bare essentials for you.

We tried to put a 96 dash in a 69 truck a decade ago with no success. Take some measurements and see for yourself.

Yes you can use the factory computer. Your 94 is OBD-1 and it is quite simple. I put a 5.2 magnum into my Jeep and I used a 95 donor harness and computer. To do this, I installed the engine and transmission into my carbed jeep, then I took the 1995 wiring harness and peeled it apart. I found the part that controls just the engine is remarkably self contained and really only required me to hook up 3 or 4 wires to my factory carbed jeep harness.

For you, if you don't mind swapping cabs and boxes, you could put the 71 cab and box onto the 94 frame. While you have it apart I would peel apart the 94 wiring and keep only the engine wiring and reuse the rest of the 71 wiring.

Alternatively, you could transplant the 94 engine/trans/engine wiring+computer into your 71 much the same way as I did the swap on my jeep.

That's what I am looking for! I really just want to switch the 71 body onto the 94 frame and use the computer for engine and trans only and keep the 71 parts separate. I have checked the use of the 94 firewall and it seems to be a mountain of work with very few benefits. If you have some reference sites or should I go to wiring diagrams? I'm not the best with electrical so any help is very much appreciated. Thanks

His truck looks great! That is what I came up with from measuring both cabs, it needs at least eight inches to work. Thanks for the link!!!

Check out this:

1995 Ram Factory Service Manual


This page has your engine wiring diagram.