I have a 1978 F-250 Camper Special 2wd bbf 460 and I have a burnt 1977 F-250 390 4wd with a 4" suspension lift, I want to swap the 4wd parts from the 77 and convert the 78 to 4wd, I need to know what all I need to do and what to avoid and just plain advice on it, it's my first time doing a project of this magnitude to my truck, I want to avoid swapping bodies at all costs. Thanks for any advice

 

Do the body swap... you'll be that much ahead.

Compare the frames, crossmembers, holes, etc. and you'll quickly conclude that the magnitude of converting a 2WD to 4WD is enormous and probably exceeds reality beyond your current level of enthusiasm.

 

So what all entails the body and wiring and motor/tranny swap, mind you the 77 is gutted will need all of my wiring and basically everything except frame and suspension from the 78

 

Precisely what you want to do, take all your good 78 body, interior, wiring, and plop it onto the 77

 

Any advice on the wiring? Is there any way to kind of keep it all one piece cab and engine bay and all that wiring as like one unit, cause I hate wiring and trying to take my wiring out and make that work is going to be a nightmare

 

Sorry, I don't have any wiring advice. My 75 has five fuses lol, so it's ideal for you to learn.

 

move it all do it piece by piece if you can. its hard but not as hard as an axle swap

 

The wiring should be able to be kept mostly in one piece. But if you've never replaced all the wiring, I'd say its an excellent time to swap in a new harness. The 35 year old wiring is surely starting to deteriorate and if you're doing this much work, you might as well add a little extra and have the piece of mind.

 

he makes a good point

 

make sure to save the warranty tag off the 4wd truck so as not to have a title issue.

 

-first get the 77 to the point of being a 4x4 frame and suspension/axles transfer case etc

-this will allow you you to figure out how to take the nice 78 body off without wrecking it.

-you will need the trans tunnel cover unbolted from the 77 to reuse in the 78, and you will need to cut the same hole in the 78 floor as in the 77, and drill holes to match and re-use the clips/bolts that held it down

-you will use the complete 78 body everything (because thats what you want to have right?)

-you do not need to remove the wiring harness from either cab, just unplug it from the engine and chassis from the engine bay side
-remove the front bumper first, the front clip(hood, fenders, inner fenders, rad support, grille) of these trucks will unbolt as a unit, there are 2 bolts through the bottom of the rad support thru the frame, and 2 bolting points at bottom of inner fender to the cab, and the 3 bolts at top of inner fender that bolts to the cab, and a ground strap from the hood to the cab
-obviously undo the washer fluid lines from the cab, and remove the battery
-the cab has 4 bolts holding it, 2 you have to go thru cover plates at bottom of inner fender, 2 you have to go thru rubber circle covers in cab under back of seat and carpet
-OH, if it has the plastic inner fenders remove them completely, it makes things easier, when i mention inner fender above I am thinking of the metal inner fender that you see when you open the hood
-box is 8 bolts, and fuel lines, and unplug wiring harness from under drivers (left) side at rear of box, and helps to remove rear bumper first

-search around the site, this will help you to get started and give you the smallest idea of what you are attempting

-theres more but take lots of pictures and label where everything came from so it makes reassembly easier

 

There is nothing nuts and bolts about a 4wd conversion, there is not a thing that is bolt on or swappable. The engine cross members are entirely different, and this means that if an un molested truck is what you are after, it will be impossible to create one with a 2wd platform.
The 2wd will have to be lifted quite a way to clear the front diff. 2wd trucks are coil sprung and most F250 4wd's are leaf sprung. None of the suspension items are even close to the same, so you will be fabricating or modifying some original 4wd stuff to work.
Steering systems are entirely different as well, so you will be upgrading that too.
My last conversion with leafs ran me several thousand dollars, and that was with the work that I performed for free. The difference in sale values between a 4wd and 2wd are minimal, and the 4wd conversion is hardly justifiable.
Well the frames are similar, with a few exceptions. The frame horns are slightly different, and the frame widths aft of the cab are different from 73 to 77 trucks. The frame rise is also slightly different, but this is not a show stopper and does not make much difference one the fabrication begins.
Now the important question is whether or not you will be using a coils springs or a leaf spring. It is possible to install a 78/9 radius arm and suspension. Not a big deal really, and with a standard cab this is reasonable. Not quite as easy with a super cab and or crew cab.
The 2wd frames are not cut for the shackle pivot, and they do not have the provisions for a spring hanger, but again, this is not a deal breaker. Installing a pivot is just a tedious process, accuracy is key.
Ok, so next is the transfer case. You have two choices, install a married case, and this requires the proper transmission. Might find some difficulty making or modifying an output shaft to accommodate the early C6 and a married transfer case. So then the next option is to find a divorced transfer case, and install this. You will have to make up a cross member, but then you will have to get creative with the shifter linkage. See the 4wd trans will have an adapter or tailshaft with a pivot for a typical 205 shifter. Fabrication is the only limiting factor here.
Next and final factor will be the speedo. See your speedo works from the trans, so that being the case, you will have to get a speed reference from the t-case. If you do not, the speedo will read twice as fast when you put the case in low range. But you will be in 4 low so who cares how fast you are going.

As mentioned the steering box will have to be relocated, and the truck will require some lift. That engine crossmember has limited clearance so you will be looking at some lift to even clear it. The other option would be to remove it and replace it with a tubular unit.

X 100 on just swap the good body to the already 4wd frame, and of course the wiring harness.

 

Front clip removal:Ok then here goes, there are 5+ ways to skin a cat, here is just what works for me. I am going off memory and am a long way from my truck to go look. This worked on my none a/c 79 4x4 F250 w/standard transmission, more than once, and I used the same technique on a 79 Bronco with a/c and a automatic transmission.
Painters tape on the door front edge when opened, and a little more plus the back edge of the fenders to prevent scratches. Disconnect battery and remove. Then drain radiator.
Tag and bag each piece of hdwr, or stick it in a large piece of card board and mark it accordingly.
1. Make sure you park the truck where you can get both doors open. Or BEFORE you put it inside a narrow shop....Open each door and remove the one bolt on each side that is right between the hinges. Now put it in the narrow shop...lol.
2. Take a scribe or sharpie and trace a mark the hood hinge positions on the underside of the hood. This will be helpful come reinstallation/realignment time. Hood removal is really a 2 person job. If you go it alone, be careful, great way to scratch the hood/cowl. If the hood is all the way open, it is front heavy when you remove the bolts. I can’t really explain a 1 man job here, but it looks like a monkey f..in a football. Just get a helping hand for this. If the hinges are compressed once removed, be careful as they can pop back up easily and get a finger in the process. Disconnect the hood ground on the passenger side. Make sure you make note of the stiffener brackets (under the hinges), if you have them. Ok hoods off.
3. At the very bottom edge/back side of each fender, is one bolt.
4. Make sure if you have the front fender/front edge to frame, small support bars (some do, some don't) remove them from the frame. I would remove them from the fender side also, just to prevent anything from getting bent.
5. Masking tape tag each electrical connection point on each side of the connection and mark them like (1-1), (2-2) or A-A, B-B and so on. There are 3? Main electrical connections on the dvrs side back by the fire wall, behind the hood hinge. Tape, tag, and disconnect.
6. There is an electrical harness that runs across the back side and above the fire wall on the passenger side and goes to the starter solenoid. Disconnect from solenoid (make sure you know make note, where each elbow plug goes on the starter solenoid.) There is a plug for voltage regulator, and then lay wiring on engine. Ground wire from solenoid to eng block (remove from solenoid side).
7. Look over the area behind the headlights/behind the core support area (each side for 1 small square plug) and the windshield washer tank for a elec plug in the front end of the tank. And the rubber feed line that goes to the T up by the cowl.
8. Top and bottom radiator hoses from back side of radiator. Fold rubber hoses back out of the way and zip tie, so they do not flip back open. Is it a automatic transmission? Disconnect transmission lines from radiator and cap lines.
9. There are these 1” or 2” wide rubber straps (one on each side) on the back side of the metal inner fenderwell that attach to the firewall, disconnect from firewall.
10. Scribe mark where the bracket that support the inner fenderwell (where it attaches to the fire wall). Remove 3 bolts per side.
11. Now if you are lucky here, down on EACH side of the radiator there is one main mount bolt for the radiator core support bushings. Lucky meaning, it will come out and is not all rusty and stuck. But if it is rusty, stuck and or the head is stripped. Time for the sawzall, Red Diablo blades here and carefully cut between the top of the frame rail and the bottom of the core support. These bushings and bolt parts are available. A torch is not a good idea here the rubber bushings will smoke like crazy.
12. Have an old tire or some other similar support to set the front clip down on once removed. Put it under the middle of the core support/radiator. So you do not bend the front edge of your fenders.
13. I use 2 other FTE buddies + myself and we just pull the complete front clip off. Make sure the plastic inner fenderwell liners do not get hung up on the shock brackets. As far as by yourself, attach the cherry picker to the middle of the core support, it can be done with a piece of cable, some folks just pull the radiator and use chain. Make sure you triple ck all electrical connections and the core support bushings are free. Lift it up just a bit and ck the fenders, and then lift it up again, just a little. You want to pull it more forward than up, so that the back edge of the fenders contact the back side of the tires. Like I said, it’s doable, but a PITA as far as a one man show. 2 guys can pull it way easier.
I am NOT positive on all the electrical connections, but that is the big stuff. I am sure some FTE members are reading this and will double ck me and chime in with what ever I missed.
Or maybe they have a better hood trick? Like this pic.