Duramax/Square body swap? Thoughts?

[gr8shot]

I've got a 1988 crew cab square thats overall pretty clean and nearly rust free. I've always been a duramax geek, owned probably a dozen of them, with various degrees of mods and power over the years. Very close to pulling the trigger on a wrecked LBZ or LMM for a swap. Considering a body swap for a few reasons. #1, my square body is 2wd, and I'd be swapping with a 4x4 truck. I have to have 4x4. #2 better frame. #3 heavier suspension and better brakes. The IFS doesn't scare me, I'm very familiar with it, will upgrade tie rods. I appreciate the smooth ride of the IFS. I'm pretty handy with a wrench, and have done engine swaps before successfully. Built a 1995 chevy with a 12 valve cummins in it. Been driving it for years.

So all this being said, am I crazy for considering a body swap? I didn't find much for builds in here for guys doing swaps on to newer frames like this. Facebook groups provided very little info either. Just a couple useful comments saying the front body mounts line up, the rest will have to be moved. Another guy said he planned to cut out the duramax firewall and use that to keep the duramax dash and steering column. I'd rather keep the square body dash, and use a dakota digital cluster.

Would love to hear some thoughts and feedback on the idea. Thanks!

 

[Grit dog]

That’s a heck of a first post!
Idk if you’ll find anyone here either that has done that. However I can’t wait to see ya do it.
I’ve thought about a similar body swap. Short box c10 on a GMT800 Tahoe. Instant LS/AWD lowered 2wd lookin sleeper. The wheelbases are close enough to make that a non issue. But that’s where it’s ended for me. No room/time to do any real Frankenstein **** in the near future.

 

[gr8shot]

I've been on a lot of forums over the years lol. I've always wanted a crew cab square body, a friend finally relented and sold his to me and I've been slowly pecking away at little items with it while I stew on ideas for what to do with it. Originally I just wanted to get the big block running and leave it as is and drive it. But it's a TBI big block, so it's a turd. And rather than dump several thousand dollars into a top end package to try and wake up the big block, I'd much prefer a diesel. And I'd still have a turbo 400 with no lockup, and get 8mpg. LBZ/LMM with a fairly conservative tune can put down 450hp at the rear wheels and live a long healthy life, tow anything I'd need, and get close to 20mpg on the highway.

Just can't find a whole lot of info on a cab swap onto a newer frame. Seen photos of finished trucks that have done this swap. But it's just google images, no real good information out there that I can find. When I did the cummins swap into my chevy, heck I had pretty much all the information found and compiled before I even started the swap. I feel like I'd be going into this one blind!

 

[KnockingDiesel]

I've been on a lot of forums over the years lol. I've always wanted a crew cab square body, a friend finally relented and sold his to me and I've been slowly pecking away at little items with it while I stew on ideas for what to do with it. Originally I just wanted to get the big block running and leave it as is and drive it. But it's a TBI big block, so it's a turd. And rather than dump several thousand dollars into a top end package to try and wake up the big block, I'd much prefer a diesel. And I'd still have a turbo 400 with no lockup, and get 8mpg. LBZ/LMM with a fairly conservative tune can put down 450hp at the rear wheels and live a long healthy life, tow anything I'd need, and get close to 20mpg on the highway.

Just can't find a whole lot of info on a cab swap onto a newer frame. Seen photos of finished trucks that have done this swap. But it's just google images, no real good information out there that I can find. When I did the cummins swap into my chevy, heck I had pretty much all the information found and compiled before I even started the swap. I feel like I'd be going into this one blind!

I am in a similar position. Building a crew cab dually 4x4 from 3+3 C30 I have everything but engine and trans. I looked into this wanting to go with an LBZ and it’s a lot more labor wise. The mods to fit the cab to a new frame are a lot harder than mods to fit a newer engine to older frame. The difference being like you mentioned, better brakes, suspension, etc.

In the end I think a gas engine would suit my needs better. I have a diesel dually and and the cost of fuel/maintenance to me for as much as I’d use it doesn’t justify the extra cost. Power is nice and the fuel economy is great but a gen v6.0 L96/6l90 with low miles is 5k or so LBZ/Allison $10k. The harnesses and hardware are are 2-3 times cost on D-Max vs LS.

Not sure how much you’d do yourself but I burned my eyes welding and my colors are off so I can’t do wiring without a helper for colors. So I have to buy off the shelf stuff.

The biggest issue I had was firewall mods and hiding 10” of radiator/intercooler/condenser between the grille and engine.

I seen a few on YouTube but not a lot of info since it’s not a common swap. You’ll find more on Cummins swaps. Most support you’ll find for swaps is engines/trans into square body frames.

Good luck on your project.

 

[gr8shot]

I am in a similar position. Building a crew cab dually 4x4 from 3+3 C30 I have everything but engine and trans. I looked into this wanting to go with an LBZ and it’s a lot more labor wise. The mods to fit the cab to a new frame are a lot harder than mods to fit a newer engine to older frame. The difference being like you mentioned, better brakes, suspension, etc.

In the end I think a gas engine would suit my needs better. I have a diesel dually and and the cost of fuel/maintenance to me for as much as I’d use it doesn’t justify the extra cost. Power is nice and the fuel economy is great but a gen v6.0 L96/6l90 with low miles is 5k or so LBZ/Allison $10k. The harnesses and hardware are are 2-3 times cost on D-Max vs LS.

Not sure how much you’d do yourself but I burned my eyes welding and my colors are off so I can’t do wiring without a helper for colors. So I have to buy off the shelf stuff.

The biggest issue I had was firewall mods and hiding 10” of radiator/intercooler/condenser between the grille and engine.

I seen a few on YouTube but not a lot of info since it’s not a common swap. You’ll find more on Cummins swaps. Most support you’ll find for swaps is engines/trans into square body frames.

Good luck on your project.

Thanks! I actually helped a buddy do a cummins swap into his 85 chevy dually a while back and it was pretty easy overall. We used Rob Bonney engine mounts, cross member and frame boxing kit. Welded it in and the cummins dropped in like it was made for the truck. It's pretty slick, built 47RH and an NP205 with twin sticks so he can even do 2wd low range if he wants. He restored the whole truck and it's a garage queen now, gets driven on the weekends and what not, very beautiful truck, and the cummins runs great. Hasn't put enough miles on it to make it start leaking yet! Takes it to a few car shows and local things, thats about it.

My goal is to do something similar, but drive it more than that. I'd probably get by just fine with an LS too, and I'm a big LS fanboy. But this is more of a toy than a daily driver for me, so it's more about what I want, instead of what's the most practical. I've got a car that I DD for the mileage, and a crew cab LLY for most truck things that I need to do. Most workout this truck would get would probably be pulling my boat to the lake.

 

[SquareRoot]

Where there's a will and enough beer there's always a way. If you can cut, grind and weld you can make any body fit any frame. Some people fear the unknown; It's always drawn me like a moth to a flame. We expect lots of pics during the process. Carry on.

 

[squaredeal91]

Yes @SquareRoot I couldn't have said it better ^^ I love my 4x4 & 12 valve swap in Big yellow, And countless others.

 

[Strick]

I saw a series build on YouTube where the chassis & floor from a Crew 2500-3500 was used. You should be able to find it with a quick search.

 

[gr8shot]

Yeah I need to spend some time on Youtube, I've seen a few different builds on there. But haven't taken the time to watch any of them to see how in depth they are, and what they're doing, if it's applicable to what I want to do or not.

 

[bucket]

There was a member here several years back that had body swapped his square onto a rolling Duramax 4x4 frame. He was really happy with it and in pictures, the outcome looked great. I can't remember the member's name, but it was a tan truck. Late 70's, iirc. Maybe someone else here remembers who it was.

 

[TheBlazerBeam]

I’ve never done a swap like this but I’ve been following this guy on Instagram who has been cataloging his experience doing it. https://instagram.com/86crewmaxlb7?igshid=MzRlODBiNWFlZA==

 

[gr8shot]

I’ve never done a swap like this but I’ve been following this guy on Instagram who has been cataloging his experience doing it. https://instagram.com/86crewmaxlb7?igshid=MzRlODBiNWFlZA==

Took me a while to go through it all, but that looks to be very similar to what I'm envisioning in my head! Main difference being that I need 4x4 and that one is 2wd. He's also a heck of a fabricator! I use solid works a lot, and have lasers, brake presses and welders available at my work. So for a bit of bribery with some ice cold adult beverages, I ought to be able to get a lot of the parts that I need made for dirt cheap, or free at work. And can 3d model them myself.

Biggest hurdle for me will just be the mobility aspect. Trying to move cabs and boxes around by myself will be a struggle. Single dad, kids aren't old enough to safely help with important stuff like that. Trying to figure out what the best solution is. Thought about buying a skidsteer, using it, then selling it to recoup my money. But lets be honest, I'd never sell it once I got used to having it around. An A-frame is an option. But a lot of the work will have to happen outside, so moving an A frame on a gravel driveway isn't a great solution either.

 

[TotalyHucked]

I've seen it done a few times, it's not that bad if you can fabricate. It's pretty much just fabbing new body mounts and bumper mounts. The one thing I hate is how far down the newer style frame hangs, you can see it from a mile away. But otherwise, it's not bad. Gauges are really the only other challenge, I've seen a couple guys use the NBS gauges and mold them into a squarebody bezel. Doesn't look half bad.

 

[gr8shot]

I've seen it done a few times, it's not that bad if you can fabricate. It's pretty much just fabbing new body mounts and bumper mounts. The one thing I hate is how far down the newer style frame hangs, you can see it from a mile away. But otherwise, it's not bad. Gauges are really the only other challenge, I've seen a couple guys use the NBS gauges and mold them into a squarebody bezel. Doesn't look half bad.

Yeah I'm not a huge fan of how far the frame hangs down. But I think in my case I'd want some sort of steps anyway. I've got young kids that I know would want to ride around in it, so they have to be able to get into it. And while I'm not necessarily an old man yet, I do appreciate the convenience of being able to get into a truck a bit easier with steps. So hopefully that'll hide the frame a little bit.

I like the look of the dakota digital gauges they make for the square body, and I've seen them working with duramax swaps, so I know it's at least possible, not sure how difficult, but possible to make them work.

 

[Ricko1966]

Took me a while to go through it all, but that looks to be very similar to what I'm envisioning in my head! Main difference being that I need 4x4 and that one is 2wd. He's also a heck of a fabricator! I use solid works a lot, and have lasers, brake presses and welders available at my work. So for a bit of bribery with some ice cold adult beverages, I ought to be able to get a lot of the parts that I need made for dirt cheap, or free at work. And can 3d model them myself.

Biggest hurdle for me will just be the mobility aspect. Trying to move cabs and boxes around by myself will be a struggle. Single dad, kids aren't old enough to safely help with important stuff like that. Trying to figure out what the best solution is. Thought about buying a skidsteer, using it, then selling it to recoup my money. But lets be honest, I'd never sell it once I got used to having it around. An A-frame is an option. But a lot of the work will have to happen outside, so moving an A frame on a gravel driveway isn't a great solution either.

Put up an A frame and leave it,that's what I did.