This is the only forum I could think to post this in. If I'm wrong, please correct me.

I am picking up an 82 pickup this coming week for parts. My brother needs body panels and glass for his 81, and I can buy a truck cheaper than parts. That having been said, I need a drive train, so I'm planning to swap a 20R from an 82, along with its 5spd and T case into my 1990 pu. The truck Is currently powered by a smoking v6 and an auto trans with no reverse.

To answer questions/statements before they are asked:
Why: because its my truck and its what I want
EFI is better: in your opinion, perhaps. In my opinion, not so much.
Do I know how much of a PITA its going to be: yup.

I plan to retain my steering and suspension. While there are advantages to the older solid axle trucks, I am going to keep my IFS for now (mostly BC I can sell the frame and axles for what im paying for the truck.) My question is, should I be looking to adapt my 90 dash cluster to work, or just swap in the 82 cluster? And aside from the wiring nightmare, and potential fuel issues, and possible alignment/fitment issues, and improbable clearance problems, what other issues should I be thinking about?
Thanks for any helpful comments, and the likely not helpful ones too

 

I have nothing to offer as far as advice. You asked and answered my question as to why.

I just hope you keep this thread updated with your progress and take some pics for all to see.

You are a pioneer for this swap as far as I know.

 

I believe you may be right. No sane person (I have never claimed to be) would want to do this swap. I'm hoping to get on it week after next, and will update thread with pics and info.

 

On the off chance anyone is interested in this swap or paying attention to this thread, I have found the 90 models dash will work just fine. Granted a new oil pressure unit will be required, and some lights (AT oil temp and such) won't work. Starting to do the important homework now so once we get started we can just roll through the punches, as bad as I'm sure they will hurt

 

You're not the only one that would prefer a carb over fuel injection. Personally, when it comes to trucks like this, I prefer working on a carb as well - it's easier for me to diagnose mechanical failures over electrical. Now when I comes to motorcycles, I'm fuel injected all the way! I'd be more concerned about downgrading from a V6 to a 4 cylinder. You're going to have significant power loss (assuming your V6 had any to begin with).

Right off hand, your major obstacle would be to determine what existing wiring will work with the 20R (BTW, a 82 should have a 22R engine). If it were me, I would keep the 1990 gauge cluster and as much wiring as possible. I would start by removing emissions (if your state will allow that). I would unwrap the 1990 harness and remove all the wiring that comes from the emissions computer. I would "split" the harness and re-wrap it into two parallel strands - one for any engine related wiring (gauges, ignition, starting, etc) and the other for everything else (lights, accessories, A/C, radio, etc). That'll clean you up and keep you from wondering "what does this wire go to?" on a lot of wires. Obviously, you'll need some emissions block off plates if you go without emissions and you should probably go with a Weber carb if you don't want the headache of an Aisin carb. The major challenge in wiring would be getting the ignition wired properly. I imagine that you could simply match up the wires going to the V6 coil to the 20R coil. You'll also have to match up the wires to the 20R alternator properly. The starter should already have a sending wire going to it so they should swap over easily too. You'll want to take the sensors (temp, oil pressure and oil light) off of the V6 and locate them appropriately on the 20R - the resistance in the sensors match the resistance in the gauges so you don't want to mix them and get false readings. A wiring diagram for your 1990 and the 1982 would be extremely helpful - I have one for a 1983 which should be mostly the same if you need it.

Mounting the engine shouldn't be too bad. I don't believe that you need to modify the frame at all - I think that you just need 20R engine mounts to replace the V6 mounts, but I'm not sure about that. And I'm fairly certain that the V6 radiator will work for you as well. You'll need to rework the exhaust from dual headers to single headers.

The driveline may give you hell. The transmission and t-case won't be the same length so you'll have to modify your tranny crossmember. You'll also need to shorten/lengthen your driveshafts and likely need to modify the shifter holes in the cab.

Honestly, it sounds like a lot, but it shouldn't be too difficult. People successfully do the opposite conversion all the time which I believe to be harder.

 

I find that the newer EFI motors are much harder for me to troubleshoot and virtually impossible on the trail to repair. I learned cars on carbs, and I don't learn new tricks well.

My v6 has enough power to successfully hold my boat in place while fishing. It is only good for a boat anchor. Period.

The worst part I think was figuring out the wiring. I sat down with both diagrams and sketch paper and basically redesigned the 90 ignition and sensor harness to work, barring the in-build catches, I should be set there. Emissions will be deleted. New exhaust. Weber carb for sure. And moving/modifying some mounts is expected. I agree, the reverse is much more difficult.

And here is today's project: my brother has water in his oil, oil in his water, and smoke in his exhaust. Very bad.

 

The motor mounts ARE different from the v6 to 4cyl and have to be moved.

 

Mounts are different. Frame is not. I don't think.

 

Well there ya go - need some modified mounts too