Ok here we go, I have a 97 f350 dually regular cab the cab corners and drivers side pillar are shot was looking at replaceing the cab. Somehow in my thought process of replacing the cab I began to wonder if i could put a club cab or possibly a crew cab on this frame I know I know if i did that i would lose the bed space and thats ok i am not running a bed on it anyway i plan on decking the frame and putting a fifth wheel on it. does anyone know if this could be done or has been done?

 

Well, I don't know but the first thing that comes to mind is wont the mid ship fuel tank sort of interfere?

 

I don't know either but the first thing that comes to my mind is titling and registration issues, the VIN is on the cab.

 

^^This^^

Before you get any ideas to swap cabs, do realize that you will need to re-register and title the truck for the VIN on the donor cab. People think it's just a matter of dropping a cab onto the frame, when in reality if you don't know what you are doing you could be commiting a felony. Don't even think about switching VIN tags, that will land you in even hotter water. IIRC the wheelbase and cab mount points are different between the 3 cab styles.

Possessing the VIN tag rivets is also illegal in many areas FYI


This is an extreme example, but he could have faced being locked up for 8 years:
http://blog.hemmings.com/index.php/2...ng/?refer=news

 

Wow! That's a wild story on that Chevelle, good read! The second car I ever owned was a '64 LeMans Convertible I bought for $500.(my first was a '69 Camaro 350 I paid $700 for, to tell you how long ago this was) After a few years I sold it to my sister, and later she sold it to an guy I knew slightly, who converted it into a GTO and later sold it for the then astronomical figure of $7K. Apparently '64 was the only year the vin was the same for a v-8 Lemans and a GTO. I saw the car a few years ago, I imagine the guy who owns it now thinks it's a real GTO. I would never tell him if I talked to him though, bearer of bad news and all that.

 

I normally am on the Diesel section for OBS trucks, and I did do auto body for 20+ yrs before leaving the business. Having said that some of this comes from memory and some from some old frame sheets I saved. There are several different wheel bases 117.0" (reg cab/short bed), 133.0" (reg cab/long bed), 139.0" (ext cab/short bed), 155.0" (ext cab/long bed). I do not have crew cab wb #s, sorry. The frame dimensions for F-150, F-250, & F-350 2WD are the same for the same wb. The frame dimensions for F-250 & F-350 4WD are the same for the same wb. The F-150 4WD has its own frame dimensions for each wb.
I'm going to assume that your truck is an F-350, 2WD, reg cab, long bed, dualy from your info. The frame "grows" in length for the longer wb between the transmission x-member front bolt hole and the center of the rear spring front mount hole. This is also the area where the kick up in the frame changes (moves rearward) to keep the cab level with the bed. I think you will loose the front fuel tank as the new longer cab will probably either block access to it or cover it completely (not positive). The longer cab will not sit on the frame properly due to the kick up being in the wrong area for it to lay level/flat. You also will not have the body mounts in or on the frame in the correct places due to the original cab being shorter.
These things do not mean that it can't be done, but you will need to raise the front of the cab & the rad support to level the sheet metal since you can't drop the back of the cab. You will need to install new mounts as needed. Creating your own bed for the 5th wheel is a good idea but you need to be sure it is located over the rear axel and still have enough room to not hit the cab during a turn & while backing up. Also be honest with yourself regarding you fabrication skills and tools you have to complete the project.

 

Thanks everyone for all the input. I do realize the registration and vin issues and will be looking for a donor truck with clear title. I will be loosing the mid ship fuel tank my original plans was to build a behind the cab tool box 24" wide up to the bottomn of rear window acess doors on the sides. I also thought of a putting a sleeper unit on it just for the storage. The extended cab thought process came about after finding the extensive rust issues on current cab. from all caculations (quessing no real measurments) it looks like an extended cab will fit (does anyone know how much longer an extended cab is than a reg cab?)

 

before you get too carried away,you can just drive it to a couple body shops for some quotes to repair the rust.

 

Ext cab 22" longer (139-117=22 or 155-133=22)