The guys at the local junk-yard told me that converting a '78 f350 crewcab 2x4 to 4x4 would be a simple bolt-on job with a donor truck. They said the f350 frames were the same 2x4 or 4x4 (they were pre-drilled for what ever the frame would end up as 2x4 or 4x4) and that I just had to unbolt the old and bolt on the new. Am I dreaming? It seems that moving a cross-member to fit the transfer and then ripping out the I-beam front suspension and bolting or welding on some spring mounts for the dana 60 springs, is really all that needs to be done (besides steering and driveshafts). Am I still dreaming?
Thanks.

 

Yup, your dreaming. I think only vehicles with straight axles are the same frame and they are rare. If it has twin I beams it is not the same frame as a 4X4. Hawkrod

 

Okay, back to the drawing board (as with so many other FTE members, in my area there just aren't any of these around so I have to find a way to put something together.
Are the '73-'79 f150, f250 and f350 frames the same width? i.e. Could I buy an f150 or f250 crewcab and swap in a 1ton drivetrain?

 

Are Crewcabs that common around you that you can do that? where are you? I am coming to buy up all those crews! LOL. For the most part the answer is yes you can mix and match all light duty parts but there are exceptions like pre 78 4X4 (well 77 1/2) and Super Camper Special. As long as the frame is the same width for the component you want it will swap What that means is for example an SCS dana 70 1 ton rearend should bolt into a Hi-boy but not into an F250 2 wheel drive. If you have found a good Crewcab Cab buy it and save it, they are hard to get. Hawkrod

 

Well no, crews are not common here so I have to find out what I can do with what little we've got up here. Is it possible that the junk yard guys were talking about '80-'86 trucks ... it seems in that forum that the conversion IS more or less a bolt-on job.
Thanks

 

Yes, the 80 and newer is pretty much a bolt on. I am still wondering how hard it would be to bolt 80 and newer 4X4 parts onto a 79 and older but I have never taken the time to sit and look at it. I know the 80 and newer frames are wider but that could be accounted for when you made the inner pivot mounts. Hmm. LOL Hawkrod

 

Hmmmm, you see, I've got the chance to buy a '78 crewcab 2x4 long box. The body is fair: cab and box (no holes) ... nothing a little sandblasting won't cure. Its going for $1700. I don't want to give up the long box, so I'm still stuck finding a 4x4 crew/long box frame ... think I could put it on a '80-'86 frame and drivetrain?

 

This depends on what kind of suspension you want to use. If you want leaf springs up front, which is the easy way to go for ease of installation, then the 80 and newer front axles will be a nightmare as the driver's side perch is cast into the housing so you can't move it in. This means you have to build custom spring hangers and shackles that sit outside the frame. It can be done but it will be a lot of work. If you can get the front axle from a 78/79 then you'll be golden. I'm not sure how the rear width compares but moving spring perches on an axle is a very simple task as both sides can be removed and then re-welded wherever you need.

If you wanted to get fancy and do a coil spring front suspension you could probably use the wider axles with ease. I'd just be leary about putting that much weight on coils, being a crew cab. I think they'd have a tendancy to sag quite fast.

If you get a chance seach in the offroad forum for info on the conversions. There are a couple really good threads there. I believe one of the guys who laid it out well posts as "scottie2hottie". If I'm remembering the name correctly he's done several conversions.

 

No, I was thinking in terms of adapting a TTB front end to a 2WD chassis. The straight axle 80 and newer actually uses the same front axle as a 79 and older. As far as weight goes, the crewcab is not all that much heavier, A Crewcab shortbed is only a few hundred pounds heavier than a regular cab long bed (okay, maybe 500 pounds, I need to find my weight slips! LOL). Hawkrod

 

What ARE the differences in the frame? i.e. how much fabrication would I be faced with?
Thanks!

 

The frames do not share any common parts, they are shapped differently and have different crossmembers and locations. Frabrication? I would find a 77 1/2-79 F250 4X4 frame and lengthen it to fit the Crewcab. Hawkrod

 

Ouch! those frames do sound too different! Yeah, I'll stretch a 4x4 f250 frame, sounds like a plan!
Thanks!

 

This is just my opinion so take it how you want but personally I'd much rather build a custom front suspension than stretch a frame on a LONG truck like that. The only way I can see the stretch being anything other than a total nightmare is if the frame widths were the same for both trucks and you could take the back half of the 2wd and weld it to the front half of the 4x4. Otherwise you're going to have to cut a section out of some other frame and splice it into the middle, giving you 2 joints on each frame rail. That means a lot of extra support needed to make sure it holds up. Shortening a frame is far easier than lengthening one. If you've got the F250 4x4 donor truck it would be relatively easy to adapt the front end from it to put it under the 2wd.

Just a heads up, here's the post I was telling you about. There's some good info here: https://www.ford-trucks.com/forums/s...d.php?t=280914

 

Yes, good point, and that is how I would prefer to do it myself if I was going to try. Hawkrod

 

Thanks, I think you're right. I my case I'd be spending $1700 or less for the crew 2wd, and another $500 -$1000 for the donor 4x4, there's a lot of room to spare money-wise compared to buying a 4x4 crew and shipping or picking it up from somewhere-far-away-USA. The price-tag on those things is double/triple/or more than the cost of the two trucks!