'89 Crew Cab body to '90 Suburban frame?

[89 Crewzer]

Potentially dumb question.... I have a 1989 Chevy 2500 Crew Cab single rear wheel long bed truck. I also have a donor 1990 !/2 ton Suburban 1500. My question is rather than swap the engine / trans and f/r suspension from the half ton sub onto the 3/4 ton Crew Cab, could i swap the CC body onto the sub complete engine / trains / rolling chassis? I'm going to put a short bed on it as well. Then i would have to lengthen the frame, driveshaft, brake lines, wiring, emergency brake cables etc. I'm also intending to swap the front clip, front and rear doors and all wiring for the cab and engine / ECM.

Is this a dumb idea or should i just stick to my original plan of swapping EVERYTHING off the sub onto the original crew cab body and 3/4 ton frame. As i said my end goal is a 1/2 ton Crew cab shortbed with the TBI 350 and 700R4 trans from the sub and all the power accessories the sub had onto the CC.

Tim

 

[HotWheelsBurban]

Potentially dumb question.... I have a 1989 Chevy 2500 Crew Cab single rear wheel long bed truck. I also have a donor 1990 !/2 ton Suburban 1500. My question is rather than swap the engine / trans and f/r suspension from the half ton sub onto the 3/4 ton Crew Cab, could i swap the CC body onto the sub complete engine / trains / rolling chassis? I'm going to put a short bed on it as well. Then i would have to lengthen the frame, driveshaft, brake lines, wiring, emergency brake cables etc. I'm also intending to swap the front clip, front and rear doors and all wiring for the cab and engine / ECM.

Is this a dumb idea or should i just stick to my original plan of swapping EVERYTHING off the sub onto the original crew cab body and 3/4 ton frame. As i said my end goal is a 1/2 ton Crew cab shortbed with the TBI 350 and 700R4 trans from the sub and all the power accessories the sub had onto the CC.

Tim

The frames are different. Be simpler to move the Burb running gear into the crew cab.

 

[89 Crewzer]

The frames are different. Be simpler to move the Burb running gear into the crew cab.

pardon my dumb questions but different how? Different body mount locations? Obviously it's wayyyy shorter. I don't care about load capacity or physical thickness of the frame, I'm wanting a half ton truck and the most i'll ever carry in it is a motorcycle. From the firewall forward the front clips will interchange so those mounts are the same. Do the forward most cab mounts line up? I'm assuming the rear mounts and middle crossmember are different. Also keep in mind i'd also have to lengthen the WB from 129.5" on the sub frame to 149" to put on the short bed. The reason i ask is i want to take almost everything from the sub and transfer it to the Crew. The engine and trans, the brake system with the rear ABS, the steering column, the 1/2 ton front suspension, the rear 1/2 ton rear end, the front and rear doors complete with wiring, the dash with wiring and even the interior.

So i understand there would likely be fabbing body and bed mounts and stretching the frame and the other stuff. So whats so different to make this idea unfeasible?
Tim

 

[HotWheelsBurban]

Pickup frame has a different shape and kick up behind the cab, to meet the bed floor. Suburban has no bed, so the frame is a different design with a different contour.
The Burb parts could be moved to the crew cab frame much easier. Biggest difference there is the springs are different lengths and the 2500 front suspension is a little bit larger than the 1500.
Not sure of the exact wheelbase of the square body CCLB, but the OBS one is 168.5" (I have one that we've driven almost daily for a year). I would think the squares would be close to that measurement....
The front suspension and rear axle and springs are a bit sturdier than the half ton ones; no reason to change that and it will be easier to shorten the frame on the pickup, than to convert the Suburban frame to do what you want.

 

[89 Crewzer]

Pickup frame has a different shape and kick up behind the cab, to meet the bed floor. Suburban has no bed, so the frame is a different design with a different contour.
The Burb parts could be moved to the crew cab frame much easier. Biggest difference there is the springs are different lengths and the 2500 front suspension is a little bit larger than the 1500.
Not sure of the exact wheelbase of the square body CCLB, but the OBS one is 168.5" (I have one that we've driven almost daily for a year). I would think the squares would be close to that measurement....
The front suspension and rear axle and springs are a bit sturdier than the half ton ones; no reason to change that and it will be easier to shorten the frame on the pickup, than to convert the Suburban frame to do what you want.

the CCLB wheelbase is 164.5" if you remove the 14" from frame behind cab / Wheelbase it's then CCSB wheelbase 150.5". I don't have any need for the 3/4 ton rear end or f suspension. I intend to air ride the truck and i also want the 5 lug front and back. I also want to use the suburban fuel tank. I have to stretch the frame if i use the Sub frame so at that point i'll fab up the bed mounts and the bed floor.

I suppose my only real question to you is or anyone else that definitively knows about the crew cab body mounts vs the suburban body mount locations. It would just seem easier and less potential headaches to set the crew cb body on the entire 1/2 ton sub frame vs switching every system and hoping it works. There are a lot of wires and connections that would be left mostly intact doing this way. And yes, you might be right and it's not really feasible in the end. I appreciate your reply.
Tim

 

[bucket]

Here's the thing, a crew cab will literally bolt right onto a Suburban frame. So that right there is a very big plus side to going that route. Figuring the best way to extend the frame is the trick. The best route will depend on the tools and skills available, as well as the desired amount of "factory" look.

 

[nvrenuf]

So are you planning to extend the Sub frame to fit?

As is, if you put the 4 door cab on the Sub frame the pick bed would be maybe 4’ long? With length taken out of both ends to get the wheel opening right.

Only the core support and front floorboard body mounts are the same. The Sub will not have the correct body mounts for the rear of the cab. You could move the mounts and crossmember over from the crew cab frame but you’ll need to make sure they fit because the crew cab’s frame is 2” deeper in that area which could change the brackets.

The rear axle is going to be right up against the back of the cab.

 

[HotWheelsBurban]

Yup, that's what I was getting at....
Suburban cargo area is only 5' long with the second row seats up. That's where the second row doors are. Burbs cargo area is 8' long when second row is folded down. The square body Burb has a 129.5" wheelbase which is 2" shorter than the long bed pickup (single cab) at 131.5". For the OBS Burb the wheelbase is stretched that 2" to be the same as the single cab long bed, but the frame and body mounts are still different because of the floorboards vs. cab and bed.
My family's had 8 Suburbans. I've worked on all of them, loaded and unloaded them, washed them....I know them well.
Before that, we had 3 square body pickups, all GMC half ton single cab longbeds.

 

[PrairieDrifter]

Yup, that's what I was getting at....
Suburban cargo area is only 5' long with the second row seats up. That's where the second row doors are. Burbs cargo area is 8' long when second row is folded down. The square body Burb has a 129.5" wheelbase which is 2" shorter than the long bed pickup (single cab) at 131.5". For the OBS Burb the wheelbase is stretched that 2" to be the same as the single cab long bed, but the frame and body mounts are still different because of the floorboards vs. cab and bed.
My family's had 8 Suburbans. I've worked on all of them, loaded and unloaded them, washed them....I know them well.
Before that, we had 3 square body pickups, all GMC half ton single cab longbeds.

I swear longbeds and burbs are the same wheelbase.

 

[nvrenuf]

I swear longbeds and burbs are the same wheelbase.

They are extremely close but there is 2” difference. Even if the were the exactly same when you substitute the 3’ or so for the rear door the bed gets really short.

 

[bucket]

So are you planning to extend the Sub frame to fit?

As is, if you put the 4 door cab on the Sub frame the pick bed would be maybe 4’ long? With length taken out of both ends to get the wheel opening right.

Only the core support and front floorboard body mounts are the same. The Sub will not have the correct body mounts for the rear of the cab. You could move the mounts and crossmember over from the crew cab frame but you’ll need to make sure they fit because the crew cab’s frame is 2” deeper in that area which could change the brackets.

The rear axle is going to be right up against the back of the cab.

Did the body mounts change at some point? I know I've seen builds were the crew cab bolted right up to the Suburban frame mounts. Pretty sure I've compared my own frames out of curiosity in the past too.

 

[nvrenuf]

Did the body mounts change at some point? I know I've seen builds were the crew cab bolted right up to the Suburban frame mounts. Pretty sure I've compared my own frames out of curiosity in the past too.

Honestly, I'm not sure on a Sub. I just know that when people put a truck cab on a Blazer frame they always need/want the crossmember with body mounts for the back of the cab from a truck, I'm guessing a Sub will have similar issues.

I'm not sure what year it started but around the late 70's Blazer frames went from being completely straight to spreading out wider about a foot or so in front of the rear spring front hanger, did Sub's also do this? That might be tricky for a truck bed too.

Also, a Sub frame is fairly level in front of the rear axle so if converted to a pick up I would think you'd need to use a fair sized body lift on the front bed mounts.

 

[bucket]

Honestly, I'm not sure on a Sub. I just know that when people put a truck cab on a Blazer frame they always need/want the crossmember with body mounts for the back of the cab from a truck, I'm guessing a Sub will have similar issues.

I'm not sure what year it started but around the late 70's Blazer frames went from being completely straight to spreading out wider about a foot or so in front of the rear spring front hanger, did Sub's also do this? That might be tricky for a truck bed too.

Also, a Sub frame is fairly level in front of the rear axle so if converted to a pick up I would think you'd need to use a fair sized body lift on the front bed mounts.

The Blazer frame changed in '78.

I'll have to take a look at my frames and cabs again. I'm 95% certain that a crew cab bolts right on to a Suburban frame.

 

[KnockingDiesel]

I was about to post something about this regarding a truck I seen online.

It seems like a regular cab long bed or suburban frame. I think it’s the long bed frame since the gap between cab and rear wheel is decently spaced. I have a clean 4x4 rclb K30 frame.


This is one of the nicest square bodies I have ever seen. It’s on Pinterest if anyone has any info I’d love to know about it.

I’m piecing a 3+3 build now to build over the winter and was dead set on cclb drw 4x4 but this truck is really nice.

You must be registered for see images attach

 

[89 Crewzer]

So are you planning to extend the Sub frame to fit?

As is, if you put the 4 door cab on the Sub frame the pick bed would be maybe 4’ long? With length taken out of both ends to get the wheel opening right.

Only the core support and front floorboard body mounts are the same. The Sub will not have the correct body mounts for the rear of the cab. You could move the mounts and crossmember over from the crew cab frame but you’ll need to make sure they fit because the crew cab’s frame is 2” deeper in that area which could change the brackets.

The rear axle is going to be right up against the back of the cab.

It's going to 100% be a shortbed crew. It won't be like the pic you posted. I'm going to research the EXACT wheelbase differences on the intended Crew Cab Short Bed vs the Sub frame but i think it's like 20" that will need to be added to the frame to accommodate the shortbed. I Have a really great fabricator lined up to cut and stretch the frame and also add a crossmember to support the rear CC cab mounts. Obviously i'll also be extending the driveshaft, the wiring, all of the fuel lines to jive with the EFI and the brake lines.