Hello everyone, I've been lurking on this site for years and just recently became a member.

I have a '73 4x4 f250 regular cab that I started to restore about 14 years ago, life got busy and I haven't done anything on it in about a decade. Now married with kids and i'd like to take the cab off my parts truck a '79 2wd f250 and put it on the '73 frame. I am planning on extending the frame 33.5" and looking for any advise and info I can for the build, my first question is are there any threads that anybody knows of where somebody has extended the frame on their build to accommodate a crew cab? I did a couple of searches but turned up nothing.


Thanks

 

Welcome. You'll be glad you joined up. Lots of good info and members on here. I do not have a thread for it, but I did this exact process for my '77 crew 4x4. Reason being, when I got the truck, the cab was mounted on a '77 highboy regular cab frame. It had a flatbed on it too. I wondered why this had been all been done so I decoded the VIN and figured out that the cab was actually off of a 2wd chassis from the factory. Kinda turned me off after I figured it all out, but the cab was very solid with no rust in the usual "crew cab rust areas" so I decided to go on ahead with the project. I assume you're wanting to stretch the frame to accommodate a short bed or maybe even long bed? The best suggestion I can give you is to find another frame with the same dimensions as yours and cut out the amount of rail that you need. That way when you're done stretching you won't be able to tell anything has been done. We (my father in law helped me on the project) cut the frame right behind the cab and put the extra length in there. If you have more questions let me know. I can post some pictures later of the process

 

Yes, I'm extending the frame so that when I'm done I'll have a crew cab long box.

Since you cut right behind the cab did you then have to move the cab mounts? Was there any interference with the frame height, I figured I would have to cut it somewhere below the cab so the frame wouldn't dip or hump under the crew cab, also might save me from moving cab mounts(not sure on that yet since I haven't crawled under the crew cab yet.)

I was planning on having some steel bent to match the frame (I used to be a certified welder and I still have most of the welding and fabricating skills.) so it would be new steel but look like the old frame. I was also thinking of boxing the frame the length of the inserts plus about 10-12" either side of the seams, what are your thoughts on that? I've never boxed a frame before but I see it all the time on TV

 

Extend the frame under the doors of the cab and you won't have to worry about the hump of the frame. It's flat and straight there.

 

That was my thought

 

If you're looking for fast or cheap you can always body lift the cab to clear the hump...

 

If I have to cut it somewhere I might as well make it easy for myself

 

If the goal was to avoid a frame cut you could do a body lift on a cab and chassis truck, which would 2wd, and swap the axle under, or could get a newer crew frame and modify the cab mounts.

Its work any way you slice it.

 

Actually, I had thought about trying to find a wrecked truck with a 7.3L in it and moving the body onto it (if the frame was straight) but that would take way more money than I have available right now.

 

The crew cab had already been mounted on the regular cab frame when I got it. Therefore, the rear cab mounts had been redrilled and mounted and all was good. SO, there was another straight section between the rear cab mounts and the front spring hangers. This is where we cut and added the new section. This way we didn't have to mess with unbolting the rear cab mounts, supporting the cab, then redrilling the cab mounts and bolting it back up. In your situation, you'll have to do all this anyway. So yes, you could either cut it under the cab or in front of the rear springs. Making a section to fit probably wouldn't be that bad either. And if you're a welder, this shouldn't be that big of a challenge. Biggest part is getting everything level and true before welding it all back together. We welded both seams, then welded plates across each seam on the back side for added strength. I plan to smooth up the welds a bit so you won't be able to tell from the outside that it has been stretched

 

Thanks for the info, this forum is amazing, I belong to a few but none of them see the daily traffic and info sharing that FTE does.

 

I have definitely learned a lot on this forum. Lots of good guys to provide accurate information. Here are some pictures of the stretch. You can see the plates we welded on the back for more support. We did have to redrill the holes for the front spring hangers but figured that was easier than remounting the cab. You can cut wherever you want since you'll have the regular cab off anyway.

 

Thanks for the pics, I'm starting to think the frame stretching will be the least of my worries.

 

Ok, so the wife is out of town this weekend so I'm hoping to find the time to stretch the frame, anybody who has done it am I right with the length? Is 33.5" longer right? Does anybody have the original specs from ford as to what the frame lengths are?


Thanks.

 

I went by wheelbase when I stretched mine which will give you the same number. According to the thread below it shows the regular cab wheelbase being 133", short bed crew cab wheelbase being 150" and long bed crew cab wheelbase (only in 2wd of course) being 166.5". I found on the ranger station website that the crew cab wheelbase from 1978-1997 was 168.4". So I guess maybe they made them a little longer after '77?. All that being said, it looks like the 33.5" should get you where you need to be.


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