Body/Frame Swap...Talk Me Out of It

[Kilian]

I had posted in the Drive Train subforum a week or so ago about if it was possible to convert a 3/4-ton 2WD to 3/4-ton 4WD. The consensus of responders was it was easier to swap in a 4x4 frame or just leave as 2WD and go with limited slip rear end for better traction.

Well, since then I've not come across any 3/4 ton limited slip rears for sale but have seen a couple of 73-87 3/4-ton 4x4 frames with axles available in my area, in decent shape, and around the $400-500 range which has got me back thinking about doing a swap.

As part of the 2WD project I had planned to remove the box to paint the front of the box and back of the cab, as well as remove the front fenders to do some minor rust repair on a fender and the inner fenders. SO now I'm thinking that with all that removed, why not just remove the cab and engine while I'm at it and put it all back on a 4x4 frame?

What I'd like to hear is if anyone has done a basic frame swap from square body 2WD to 4WD frame and what the pitfalls are? I know that swapping in the 2WD cab would require some floor modification for the different hump size. What other hidden issues are there that raises the difficulty level?

 

[80BrownK10]

Just put a body lift on it and that would fix the transmission hump issue I bet. Haha

Seriously I don't know but I do know it has been done plenty of times

 

[eskimomann209]

@80BrownK10 is right. If you’re going that far. I too would lift the body To help clearance issues. And if you have the axles and what not converting to a leaf spring front end is cake. I would say it can easily be done in 4 hours. Buy a front crossmember (adds 3” of lift ) mount it and figure where the rear ones go according to where the front ones are.

 

[eskimomann209]

Or swap body’s on the frame with the body lift. No hump issues and no welding. there are honestly a bunch of ways to do this. Bigger problem is how do you want to do it? Custom , close to oem? Leaf spring, 4 link w/coils? options are limited only to your budget
Also make sure your body mounts match up with the year frame you have.

 

[bucket]

I've been planning such a swap and have acquired all the parts to get the job done. I'll be converting my frame and modifying my floor. There's a lot of details to tend to, but my frame is clean and it's a Suburban.

If it were a regular pickup, I'd probably just swap the frame though. It's much easier to maneuver a single cab and bed around than it is an entire Suburban body.

 

[Crispy]

Theres a guy i follow on instagram thats documenting this same build on his youtube channel. I havent watched any of it but it seems like a handful. Definitely hard work with a great payoff at the end if not rushed. https://www.youtube.com/channel/UCPDxWxOyQvA3S4d_SUPgUIQ/videos

 

[shiftpro]

Body lift.... umm hold on.
No more than 1". It will give you some clearance but probably not enough.
Any more than 1" body lift is a bad idea and really a .
Cab will eventually wiggle around. Wear out bushings.
Plus it looks stupid.

If you want a big 4x4 and have fab skills you can hang a B52/54 kit on a 3/4 ton 2x frame to convert it.

http://diy4x.com/product.php?productid=17715&cat=250&page=1

 

[waterpirate]

What you are proposing is whole lot of work. Emphasis on work. Any chance of you buying a 4x4 and swapping in your good parts rather than your idea? Just saying.
Eric

 

[Kilian]

Thanks guys for the responses. My end goal is for the truck to be pretty much stock in equipment and appearance but not a restoration back to how it left the factory. For example I've acquired the parts to add AC, cruise, intermittent wipers, etc.

What differences in cab mounts between 3/4 ton frames do I have to be aware of? 73-80 vs 81-87 or something else?

 

[bucket]

For your '83, an '81-up frame would be more of a direct swap due to minor differences in the cab mount bushings and front bumper brackets.

 

[SquareRoot]

Just do it. The hell with what others think, the economics that don't make sense, the time and effort or the rational. I've done more stupid things than this. Some worked, some didn't. You can't replace the sense of accomplishment or put a price on hindsight. Now go get r done.

 

[shiftpro]

If you want a big 4x4 and have fab skills you can hang a B52/54 kit on a 3/4 ton 2x frame to convert it.

http://diy4x.com/product.php?productid=17715&cat=250&page=1

Just to clarify, and just for everyone's data bank...
when I say 'big 4x4' I mean 38-40" tires, lots of wheel travel for some pretty serious wheeling. Would also need crossover steering and big ass long shocks, one tons and ****..
BB of course..
wife friend who doesn't mind you live in the shop..

 

[80BrownK10]

Just do it. The hell with what others think, the economics that don't make sense, the time and effort or the rational. I've done more stupid things than this. Some worked, some didn't. You can't replace the sense of accomplishment or put a price on hindsight. Now go get r done.

Some folks don't always get this. They say why not just buy another one or buy such and such.

Well sometimes you only have so much money and unless you go get a second job or do something on the side for more money you can't change your income but you have the time to do something. So you spend $200 and do some work on something vs spending $500 on a new whatever your working on or a turnkey item.

 

[EvilGenius]

In a way swapping frames is very similar to replacing a 4x4 truck's cab with a donor 4x2 truck's cab. That's the process I've been going through. It hasn't been hard or complicated. Moving the cab from one chassis to another was done with my engine hoist. It's practically a one man job although having another set of hands to help align things helps a lot. Check out my build thread for pictures of the cradle I made to lift the cab with the hoist.

The transmission tunnel for sure has to be changed when swapping cabs though. The tunnel shape changed a few times through the years where it meets the seat area. For a 1983 cab you have two options for swapping the tunnel, both of which will have to come from a donor cab:

1. Use a 1981-1983 bolt-on 4x4 high hump tunnel along with a floor patch from a 1981-1983 4x4 cab that transitions from the tunnel to under the seat as it differs from 4x2 cabs.
2. Use a 1984+ tunnel patch that is non-bolt in. This patch also needs to be cut far enough to include the transition under the seat as it differs from 4x2 cabs.

In my opinion, the frame swap is the way to go. There are some good threads on here of people modifying their 4x2 trucks to 4x4, like this one or this one. To me, those are sweet builds but they look like a ton of work to tackle compared to a frame swap. It's your project though. Good luck with whatever you decide to do!