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Squarebody Mega Cab

Suburban transforms into crew cab short bed

muddybuddy

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This thread is for the general discussion of the Item Squarebody Mega Cab. Please add to the discussion here.

Please pardon the brain dump here.

Always had a soft spot for the extended crew cab western haulers of the 80’s, and was looking for one back in the mid/late 2000’s, but on east coast if there were any, they were likely casualty of rust, and I never ended up finding one.

Fast forward to today. Modern truck proportions have really changed since the 80’s. Cabs are more spacious and can be had with all the creature comforts you find in high end suv’s. Of course the price of one of these brand new is crazy. Add in the growing popularity of pickup trucks, and these newer crew cabs are everywhere.

My situation: I have a 3yr old and a wife who has said she will never drive a crew cab (she wants an suv, and grew up driving suburbans, so she can handle the long wheelbase overall length). She also said the k5 i bought was silly and didnt understand it. Once I got the soft top on it and took our son out in it, they were both hooked. Now my wife loves the blazer. The goal of this build is to change her mind about what a crew cab can be, while making a modernized squarebody crew cab that can carry my family comfortably; a crew cab she will want to take on road trips because it has everything. While I’m at it, i do want it to have modern power, and maybe not 700+ hp like the ford raptor or ram trx, but enough to have fun

The squarebody crew cab, while awesome as is, has a small back seat, which sucks for a car seat and adult leg room for extended periods of time. Back in the day, they served their purpose, but unfortunately it wont serve mine. If I want to convince my family this will be our go-to road trip vehicle, it needs more space.

The suburbans have the rear seat about 3-4” further back than the crew cabs, and as such, have more space in the back seat. My plan is to create extra space in a pickup format, so naturally this seems like a great starting point.

The suburban also has some other advantages I plan to take advantage of. First, the lack of saddle tanks, means the floor is flat, and the seats can fold flat forward, allowing for decent amount of weatherproof flat surface area for carrying tool box, luggage, etc. that you dont bave with a standard crew cab. This flat floor will also give me more flexibility for installing modern seats, without having to work around the humps. I will plan to use a 40 gal suburban tanks between the rear frame rails, so will have large capacity with a simpler fuel system vs 2 saddle tanks and the extras that go along with having 2 tanks.

Anyways, as is stands currently my vision is:

-K30 crew cab frame
-Suburban body, cut down to add additional space behind the factory seats, with pickup truck back panel. (Suburban roof line is higher than CC starting at 2nd row, I’ll talk about the couple options I’ve been working through to address this shortly)
-short bed (will see how proportions look, as to whether bed is modified or left stock; stock would be ideal so I can leverage aftermarket accessories without having to modify stuff); gas doors removed for clean look
-40 gal suburban tank, rear tail light filler made by LS Fabrication, will make it much easier since the factory gas doors will be far away from suburban tank. Dont want to add door into bed behind wheel.
-modern interior from a recent denali/high country (heated/ventilated seats, center console with rear heat/ac), TBD on the dash, thinking it may just be factory square, with aftermarket gauges. Door panels will be an update of the factory square panels.
-dont have front clip yet, so have flexibility on that, not sure yet if will be round eye or quad headlight setup.
-tundra (1st choice) or titan (2nd choice) roll down rear window (may be a pipe dream, we will see)

Powertrain/drivetrain:

-LT1/10L80 (still working through how challenging this will be vs other swaps, but this would be the target)
-need to work through tcase options, will try to stay pass drop if I can, but may not be possible, need to see whats out there. Even thought about a divorce 205 with cable shifter
-60 front with big brake setup
-AAM 10.5/11.5 rear

Suspension/tires:
-4-5” lift
-KISS answer would be ORD leaves front and rear, but will give Stephen a call to see what he thinks best approach is for this build’s goals
-35’s on 17” steel wheels with dogdish hubcaps (i know 18’s are out there, and may end up that route if cant make 17’s work)

I’m currently in parts gathering mode for the body, thats the #1 priority to get the cab ironed out and then figure out what I need to do to frame/bed to get it looking the way I want it. I wont be making any cuts until have all the body parts needed to get it weather tight. Hoping to be at that stage this fall before winter.

Since this is just the first post I’ll pause there for now on the ‘justifications’ for this build lol. Certainly this build will be expensive, but I love squares and I would rather have a badass unique truck that nobody else has vs buying a newer crew cab everyone does. Hopefully the build costs less than buying a new one…we’ll see

Edit:
Placeholder for items for ideas to incorporate into the build. Not necessarily items to be used, but list for me to remember where i found things. A place to jot them down:

Valved exhaust (similar to mild to wild in c6 vettes)

US wheel 17” wheels for hubcaps

Universal bed extender

Truxedo roll up tonneau cover

Amp power retractable steps (this kit is square specific but expensive)

Soundman ipad mount

Remote start, locks, windows

LT swap harness mod and other LT swap items

One piece rear window kit
 
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Here are some pictures i’ve saved over the years I’ve found on various forums (not my truck obviously). I will be doing cab and truck bed, the first pics illustrate the roof line difference between the suburban and pickup.

This helps show where I’m headed, and one of the challenges/decisions I have to make early on, aside from how much space I add behind the rear door - the roof line. The suburban pops up at the second row vs the crew cab. I can either reskin it and change the structure, or embrace the extra height and add in a “modern” high mount brake light and deck light for the bed.

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Here is a build from squarebody syndicate. Here they started with a crewcab and added 3.75” and then made some adjustments to factory long bed (10” out tot between front and rear) to get proportions where they wanted it. Wheel base was shortened 4.5”. They kept the saddle tanks, and stock style 2nd row CC seat but moved mounts back to get more leg room.

IMG_6643.jpeg
 
Where I’m starting:

-98% rust free suburban body (99% for the portions I plan to use in this build)
-Sandbasted and painted crewcab k30 frame
-drw 60/70hd
-4” front springs, shackle flip in rear with leaves removed so its super soft

(Front body mounts are lined up so you can visually see the difference between crew cab 164” WB vs suburban 129.5”)
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this past friday, i drove up to Hegins PA and picked up this (near) complete tan interior, will be good starting point to get measurements, and validate the minimum additional space needed to accommodate the suburban rear seats. I wont need all of this, but took it all. Its hard to find decent factory parts around me, so gran everything I can when opportunity presents itself.

Early on in my mind thought i might be able to use the stock rear heat/ac from the suburban, but thats mounted well away from the seats in the sub where head space isnt a concern, and the rear well that has the other components. I’ll have dead space and component space issues, so this wont work. I plan to find a way to get the center console hvac to work, which will be a much cleaner look and hopefully function better with modern tech.

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Goal: The seats/center console (or similar) I’m planning to ultimately fit into the truck. This from a ‘19 high country silverado (not mine, but combo for reference). I’ll need to think through whether to use the crew cab or tahoe/suburban console. Again have time to figure out which will look best/blend in with square dash, and what mods to the floor/trans hump are needed to fit the modern trans.

IMG_6467.jpeg
 
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That could definitely be an option if its easier to grab silverado center console without hvac and then I could add that to it.

The console without hvac wouldnt meet the dash, so that intersection would be one less item to obsess over
 
if you were closer I be after that rear ac cover. I have a blue one, but the tan would match my interior. I just need to paint is all
 
if you were closer I be after that rear ac cover. I have a blue one, but the tan would match my interior. I just need to paint is all
Ive actually got 3 of them, 2 tan and 1 grey. Have all the factory hoses, blower motor, rear heater core. Would be really good headstart for someone wanting to retrofit into their non rear-a/c burb.

If down the line someone is headed your way let me know and we can work something out. Im going to do my best not to waste anything (ie: dump run), these parts are getting harder to find so would feel guilty just throwing away good parts I wont need. Someone out there is trying to get their square back together.
 
Yes, i saw that a while back as well and was trying to find it again (neglected to save it before) but couldnt find it. Thanks for posting it!
Same for me. I couldn't find it searching. I watch a lot of YouTube videos at work and scrolled way the hell back in my history and found it. Saved it this time.
 
Thanks! I’m working to collect the parts for the back panel cut. Updates for the time being are going to be gathering parts, want to have all/most of what I need for diving i to the cut.

The saying measure twice (or 2 hundred times) and cut once, also come to mind.

If all goes as planned, I should be picking up a cab next week, so should have the parts to start planning/measuring the surgery.
 

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