I have a couple issues. It appears that a few of you have been down the conversion road. I am about to do the same. I have a 79 150 4x4 custom that my father built from junk yard parts and it is stout under the body. The body is beat up and needs to be replaced along with the steering knuckle that broke when I hit a tree.

I bought a 78 lariat 2wd that has a perfect body and good paint. They both have electrical issues. The 79 would shutdown when I was driving down the road and than all of a sudden start back. Some times it wouldn't start at all. I changed out the brain box on the left fender when ever this problem came up and it seemed to fix it. The 78 I bought recently and wouldn't start. I changed out the ignition switch, fired it up and drove it into the garage. Two months later I am ready to get started and now the 78 won't get power to the plugs and won't turn over unless I short out the solenoid and even than it just turns over. Should be simple to fix this problem.

So knowing where I am currently at. In your opinion, what would be the easier swap? Running gear from the 79 to 78 and don't disturb the body and electrical or switch the body from the 78 to the 79 and don't disturb the running gear, bushings, fittings, etc?

Are the frames different. I looked at some of the other threads and there were some concerns in this area.

The motors will be replaced. 400 w/ manual in the 79. 302 w/auto in the 78.

Thanks in advance for any help you can give.

 

If you want a 4x4 truck, than putting the body parts from the the 2wd truck would be the easiest thing to do and buy a new aftermarket wiring harness to solve your wiring issues. It sounds like you're going to keep both trucks, since you are going to put different motors in both trucks, so the question is which truck do you want the better body on?

 

Oops. I meant which ever truck I fix up than that motor will be replaced. Thinking of going with a 460. When you say replace the harness are you talking about the harness that the ignition switch plugs into or the whole kit and caboodle.

 

I had a 78 2wd and a 79 4wd. the 4wd was so rusty it was actually funny! We took the body off the 2wd in THREE pieces (box, cab, front clip) and by three pieces i mean THREE pieces. used an overhead chain hoist and swapped bodies in about a day and a half. Both were four speeds, so all we had to do was cut the hole for the transfer case shifter and thats it. Easy job took less than two days. Did not run into ANY issues regarding frame difference, wiring, things fittings etc. It went smooth as butter!

 

If you are burning up brain boxs you might want to look at you voltage regulator. I have the same problem once. Sending too much voltage out and would burn up the brain.

 

Thanks shane. Sounds like the easy route there. I got the trucks side by side in the garage right now so i'll have to rig something up.

And for the panther. I did have some brain box issues. I would be going down the road and the truck would just shut off. If I was going 60 mph than by the time the truck slowed down to 40 maybe 45 it would start running again. I tried changing distributor cap and rotor, coil, but when I changed the brain box it seemed to take care of the problem for a little while at least. Off the top of my head I don't know where the regulator is. Under the dash or hood?

By the way if anybody is interested in some photos, I could take some pics and try to figure out how to transfer them to this thread. Of course that may take more time than doing the job itself.

 

The voltage regulator is mounted just behind the solenoid on the passenger inner fender. Should be about 3 x 3 inch square and silver in color. wire plug going in should have four wires i think. I'm slightly gassed up at the moment but that should be accurate.

 

yes that is where its at. I just took mine off and drilled out the factory rivets to check it and found a burnt spot. If it is good you can rivet it back together.

 

I swapped a 2wd 78 f-150 body to a 4wd F-150 chassis too! Both mine were '78's though. And I also swapped in a 460! The frames ARE different between 2wd and 4wd, all to do with the front suspension, engine crossmember, steering box location, etc. My frame crossmember for the front of the rear leaf springs had extra renforcements on the 4wd model also. The 2wd is a twin I beam front end. Switch the bodys deffenitly. Use new body mounting hardware and bushings if you can afford it- it will make a world of difference in ease of instalation and safety. Only difference I had on the bodys themselves was the front left inner fender well. The steering boxes are in different spots, so the fenderwell is notched differently. My cutoff wheel solved that though. Or you could just reuse the 4wd one. You will also need your 4wd's steering column. Any and all electrical stuff will stay attached to the cab and front clip, except the harness that runs to the tail lights and gas tank. There are connectors so you can disconnect the harnesses from each other- just mark them well with labeled peices of tape or tags, such as a-a, b-b, c-c, etc. There are not that many of them on these old trucks. Also if you have a digital camera, you could take pics for documentation. I also took my bodys off in 3 peices. Keep the fenders attached to the core support- soooo much easyer. You could also keep all the brakes together if you disconnect the booster from the firewall and pedals so u don't have to bleed them all out. Brake pedal may also be different, cant quite remember, but since your 4wd is a manual trans you'll have to switch pedal assemblies anyway. Oh and you will need to cut out the trans tunnel on the 2wd cab also, and then bolt the 4wd removable floor tranny cover down- thats easy as pie to do with a cut off wheel, a drill and about an hour of time. But beware of serial #s doing this swap. Not that I told you this, but swap your 4wd #s onto the new body, otherwise your insurance co will tell u to hit the bricks for modifying a vehicles suspention/ drivetrain. Also you could go the reconstructed title way for registration, but I personally prefer the old, don't ask, don't tell policy. After all, if you legaly own both titles...right? Really man, its not as bad as I made it seem, good luck

 

I'm not sure how this would work, but my 79 hasn't been registered for about 8 years. The 78 I just bought is registered however neither truck is insured. So if I switch the body than I am just making the 78 into a 4wd. Should go over with the DOL easy enough I hope.

 

Correct, You would be making the '78 into a 4wd. I thought it would be easy too, but I live in the communist state of pennsylvania, and I don't know how it is elsewhere, but here regular insurance companys will NOT cover you if you have a modified engine, drivetrain or suspension. They drop you instanly if they find out. I also heard they will drop you if you have a recovery winch too, but not 100% sure on that one. By law you NEED insurance to live and drive in pa. They will consider covering you If and only if you have a "reconstructed" pa title, which has all kinds of dumb stipulations for the extra state inspection to get the title. The DMV also require photographic proof here! The two dumb rules that screwed me was it says that 50% of the tire must be covered by the wheel wells, and you must have a glossy paint job. Well, mines flat black and lifted sky high, so that wasn't gonna work. Heck, stock subarus dont even have 50% tire coverage! So i just said to myself, a cab is a part right, and I need this "part" to repair my truck, so I just switch the #'s to my new "part". I afterall own these #'s legaly. As far as my ins. co. knows, the truck is a factory stock 4X4. They will never have to pay out for it anyway since I only have liability coverage on it. Hopefully you dont live in a democrat voter state, and don't have all these dumb rules. Heck we even have yearly inspections AND emmisions testing for every vehicle made 1976 and up!

 

cannot recall what i did or said to register my 78 that i converted to 4wd in north dakota. I now have it registered in minnesota and had zero issues. I'll have to look at the title, but All i know is I had zero problems!

 

I think what I did was just register the vin of the two wheel drive cab just like i normally would. Don't ask don't tell. If for some reason you wanna put full coverage on it then I could see an issue, but with liability just give them the 2wd VIN and your good to go. The less the state knows the better!

 

Note to self. Don't move to PA. Damn I thought my state was bad. I don't think it will be that bad here. I may have to do some title changes, but usually when you deal with anyone here all you have to do is get them to understand common sense and things go fairly easy. If not you can call the insurance commissioner's office and they are pretty cool.

 

Sounds good man, good luck to you. I wish more people used common sense in pa.