Crewcab body swap on Regular Cab C&C 159.5" WB?

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Haydenh

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I believe an 80's big wheelbase cab and chassis, 2wd for both of mine.

What would really be the best option, is a heavy truck, like a c50. Fully straight, heavy frame rails you can do anything you want really. Then cut off what you don't need lol. Put 1 ton suspension on it so it rides like a pickup, or run the stock c50 leafs maybe take a few out haha. I'm not sure about frame width, but I'm sure it's plenty close to fit 1 tons under it. Probably have to move perches.
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Thank you for the frame photos! Those let me see a ton more of the frame and where bucket is running into his issues. A fully straight frame would be fantastic! I do have a 1948 Dodge 2-ton truck that has that frame, however, the body is still on it and in good condition so it'll get the full restoration. Just thought the V30 would be a cool restomod as a crew cab.
Looks like my options are to keep it as is (just swap the flatbed), get a body lift for the front to match the rear (seems a a little sketchy for me), or cut into the floor without ruining too much of the footwell and seat mounting points.

Maybe a suburban floor is setup differently and would work out easier? I'll have to look at a suburban frame and or floorpan to see. Once I'm getting into major fabrication though, I'm better off selling to buy a crew cab. I'll be happy with what I have for now!
 

bucket

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So, the part I'm talking about is visible on your truck. About midway of the driver's side door is where mine kicks up. That's probably what's giving you some grief eh? If so, I'll be interested in seeing how you address the floor. If its beyond my skillset, she'll remain a single cab with an 11' bed!

Yeah, it's that area. A crew cab or Suburban frame doesn't have that kickup that far forward on the frame. The needed floor modifications "should" be hidden below the seat. A small body lift up front will help out too.

I'll be honest though, you won't see me tackling that job anytime soon, lol. I got that project on accident and it's far down the list of projects that need done.
 

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Fat 454

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Hi - just read through the thread and wanted to weigh in here with my 10c .. we looked at putting a crewcab body on a long wheelbase single cab frame. We had all the parts and lifted the cab on. As @bucket says, if the frame kicks up behind the cab ( which our frame did ), there is no way a crewcab body will fit without cutting the heck out of the floor under the back seat. Even when you have done that, the real problem is that the cab mounts for the back of the cab are now sitting in thin air, below the frame rails, so you have to fab some kind of wierd hangars to make that work.

We did look at raising the cab, but even that does not solve all the issues, and introduces a bunch of new ones.

What will work is using a suburban frame. The difference is that the sub frame is flat between the axles, effectively the same as the crewcab frame, so the crewcab body will drop straight on. Or, cut a single cab rear panel into the sub body. If you do it this way you can move the C pillar rearward to clear the sub fold down rear seat upper mounts and still keep the fold down rear seat which is cool.

Finally there is a Cab Chassis long frame that is also flat between the rails, this might be what you have, but look to see if it kicks up behind the back wall of the cab or not. if its flat you are in business.

I have some GM frame drawings somewhere that illustrate all of this. Ill dig them out and post as soon as I get a chance. Good luck and post pics in a build thread so everyone gets to learn how to do it !!
 

Haydenh

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Yeah, it's that area. A crew cab or Suburban frame doesn't have that kickup that far forward on the frame. The needed floor modifications "should" be hidden below the seat. A small body lift up front will help out too.

I'll be honest though, you won't see me tackling that job anytime soon, lol. I got that project on accident and it's far down the list of projects that need done.
I'll be interested to see what happens when you finally get to that project. I think in the meantime I'll just leave it as a single cab and enjoy it that way! Thank you for your input on the idea!
 

Haydenh

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Here is a CC cab on reg cab long bed frame, cut down 5’ bed

Definitely an interesting look! That short of a bed would be a no go for me since I have to haul the occasional bale or two of hay (750lb bales) but nice to know it works! I saw one on one of the Facebook groups that was a lifted version and it looked pretty slick! If I was doing some sort of off-road toy then the bed space wouldn't be an issue, but since it'll be my daily replacement once my current daily dies, it'll need to be more functional. Thank you for the reference though!
 

Haydenh

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Hi - just read through the thread and wanted to weigh in here with my 10c .. we looked at putting a crewcab body on a long wheelbase single cab frame. We had all the parts and lifted the cab on. As @bucket says, if the frame kicks up behind the cab ( which our frame did ), there is no way a crewcab body will fit without cutting the heck out of the floor under the back seat. Even when you have done that, the real problem is that the cab mounts for the back of the cab are now sitting in thin air, below the frame rails, so you have to fab some kind of wierd hangars to make that work.

We did look at raising the cab, but even that does not solve all the issues, and introduces a bunch of new ones.

What will work is using a suburban frame. The difference is that the sub frame is flat between the axles, effectively the same as the crewcab frame, so the crewcab body will drop straight on. Or, cut a single cab rear panel into the sub body. If you do it this way you can move the C pillar rearward to clear the sub fold down rear seat upper mounts and still keep the fold down rear seat which is cool.

Finally there is a Cab Chassis long frame that is also flat between the rails, this might be what you have, but look to see if it kicks up behind the back wall of the cab or not. if its flat you are in business.

I have some GM frame drawings somewhere that illustrate all of this. Ill dig them out and post as soon as I get a chance. Good luck and post pics in a build thread so everyone gets to learn how to do it !!
Thank you for weighing in @Fat 454 !

So you're saying that possibly cutting out the truck frame to splice in part of a suburban frame would be the way to make it work ideally (or with a Crew)? Cutting and welding frames isn't something I'd be comfortable approaching yet and honestly would be cheaper (I think) to buy a crew instead of the conversion. It sounds like the conversion with the frame kicking up is just a recipe for pain and disappointment too? My frame is similar to Bucket's in that it kicks up midway into the cab. From the rear cab mount to the rear axle is completely flat and then kicks up another few inches.

The fold down rear seats sounds really cool! Once I get this truck all fixed up, maybe I'll watch for a suburban to chop up since I can find those cheap around me. Then it sounds like maybe just stretching the frame to truck length and it'll be good to go!

My Cab and Chassis is the longest factory wheelbase you can get in the single cab version (159.5"). I wish I could pull off the bed right now to reference, but need to weld a trailer frame together to put the utility bed onto first. So the kickup does not occur after the rear of the cab but kicks up midway through the cab to become flat on the rear mounts. Is that what you're referencing when you say it kicks up behind the cab wall?

If you do have some reference drawings that illustrate what you're talking about, I'd appreciate seeing them when you get a chance! I'm not quite ready to let the idea die yet, however, its looking like it will be more trouble than it is worth at this point unless some new information comes to light. Either way, I'll start a build thread when I take the bed off and build the flatbed, do the NV4500 swap and add in a turbo to the 6.2. Nothing too crazy but just a slow build up to be my daily. Let me know when you get those drawings posted up!
 

bucket

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Definitely an interesting look! That short of a bed would be a no go for me since I have to haul the occasional bale or two of hay (750lb bales) but nice to know it works! I saw one on one of the Facebook groups that was a lifted version and it looked pretty slick! If I was doing some sort of off-road toy then the bed space wouldn't be an issue, but since it'll be my daily replacement once my current daily dies, it'll need to be more functional. Thank you for the reference though!

4'x5' round bales then? If so, then yeah you would definitely want to stick with a standard crew cab length so you can have enough bed length with your current frame and wheelbase.
 

Haydenh

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4'x5' round bales then? If so, then yeah you would definitely want to stick with a standard crew cab length so you can have enough bed length with your current frame and wheelbase.
They're about 3'x4' or 4'x5' rectangle bales (can't remember exact dimensions). Should be able to fit about 4 before overloading the truck weight wise. Its just an occasional thing so its not a 'must have', just a, it'd be nice to fit at least an ATV for hunting or haul a few bales out to sell.

If the crewcab swap was more or less a drop on the cab with some spacers or body lift and it'd look right then I'd go for it, otherwise I'll keep it a regular cab and maybe build a removable box on the back for the dog to ride in or for me to stretch out in for a nap. Saw a cool idea on some overlanding/fabrication page that gave me an idea for my truck. Then I can have more of a modular setup, just can't haul extra passengers. Oh well!

I appreciate the input you provided and the reference photos. They helped me tremendously to figure out that this would be a major undertaking!
 

CheemsK1500

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I don't recall exactly what the frame interference was, it must have been the dip in the frame like in your pictures. The frame kicks up too soon for a crew cab to fit properly, at least not without cutting or using a body lift on the front half.

I plopped a crew cab onto a reg cab c&c frame, I put blocks of wood under the front and let the rear simply set on the frame. As can be seen, it still sits higher at the rear of the cab. I've not got any further with that project yet, but my plan was to remove any offending floor in the rear of the cab, lol.

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If you cut the back out and weld the bed to the cab, you could make your own Avalanche.
 

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