Hey guys, I just got an F450 at an auction and it has a nine foot deck. I want to add a 7' dually box. There is a 19" difference in the frame length so I will either need to move the suspension, fuel tank etc ahead 19" and cut the back off the frame (I realize there is a cut out in the frame for the diff to move up) or cut a 19" section out of the frame. What is the safest way to reattach the fram if i cut the 19" out of it? I was thinking of having a section of 3/8" plate broken with 90 degree angles so it fits tight inside or outside the "C" section of the frame then bolting the frame and plates with a dozen or so 1/2" grade 8 bolts. The frame sections could be welded together THEN bolt the 3/8" plate on. Has anyone done this? I'm very mechanically inclined and have all the tools required I'm just looking for someone with some experience to help me out with the details.

Also, I noticed the F450 rear diff is narrower than the F350 dually diff. Is this difference in the hubs or the actual housing? (I know it's not the same model of axle). Anyone who has has put a box on a 450 or 550, what did you do to make up the axle width or did you just leave everything stock width?

Thanks

 

Well, to maintain the best structural integrity, I would say cut the 19" off the back end of the frame, rather than in the middle. Then you also do away with any possbile alignment issues and other crap. I would THINK this would be the easiest solution rather than a center chop and c-section.

 

...or keep the wheelbase, and add an 18" upright box between the cab n bed...

Just a thought.

Robert

 

I was looking for an X-cab truck and had planned on putting a 7' box on it to keep the wheelbase short. I ended up buying a crew cab so even if I get the 7' box on it, I'm still a foot or so longer than I would like.

 

Isn't there a user on here who drag races with a short bed regular cab SD that he shortened the frame on? I think he actually owns a fab company. I bet he'd know something, just can't remember his username.

-Jay

 

Awhile back I saw an article were the guys from SoCal Ford owners, or something like that, resectioned the frame of a regular cab to mount a short bed. Wouldn't it just be simpler to use an 8ft. bed?

 

I think it was WEWELD, but he doesn't pictures of the red F250 reg cab short bed he made in his gallery anymore. Too bad, I liked the idea of one. He still has pictures of the frame splicing he did on his F450 though.

https://www.ford-trucks.com/forums/s...ghlight=weweld

https://www.ford-trucks.com/user_gal...2&albumid=8570

 

I have a toyota p/u with a chev small block, dodge NV4500, ford NP205 and Mercedes Unimog axles....I don't EVERY do anything the easy way

Thanks for the info and the link guys!

 

Seeing how the guy did his reg. cab, I think that's the way to go. He cut down midway on the frame, then across an equal amount, then down the rest of the way. This was done right behind the cap.

 

I used to lengthen and shorten big rigs at my dad's shop years ago, When we shorten A frame in the middle, We would cut the frame at an 45 angle, then have A piece of steel the same thickness of the frame, bent to A channel same as frame, only smaller to fit iside of frame, this piece would be about two feet long and also cut at 45 degree angle. We would first bolt it in place then weld old frame together.

 

To shorten the wheelbase of a truck you will have to change.

Fuel Tank
Drive Shaft
Brake lines
Fuel lines
Wiring

If you do have a F-450 the frame rails are straight so I wonder if you can unbolt the spring hangers move the axle assembly forward to match the wheelbase you want. Then redrill the holes bolt the hangers back on and modify the driveshaft. It will be easier to drill holes than chopping and welding and removing fuel tanks etc.

I can't remember what the Cab Axle measurement is for a swb cab and chassis and a regular P/U so how much space will you have between the cab and box ?

That space might be good for a auxilary fuel tank or tool box etc. To bolt a P/U box onto the 34" frame rails means you will have to make special brackets to bolt it on with. The factory bolt holes on the P/U box will be on the outside of the frame rails on a cab and chassis frame.

If your really hot and bothered about putting a P/U box on the truck then you will be into some work. I would leave the 9' deck it makes the truck more usefull I don't know what you are using the truck for but a F-450 is a heavy truck.

If your interested in a heavy duty P/U box you can visit normarindustries.com or rebcotruckboxes.com .

 

That's a thought, about frame being straight. I think you'd still have to install a fuel tank from a pickup, because the 450's tank is in the wrong place (behind rear axle).

 

I forgot about that another reason why to keep the flatdeck

 

I know it's going to be a lot of work to get the box on there but thats what I want. I'm no stranger to building and modifying vehicles. Also I have a 300amp MIG, oxy/acetalene, metal band saw, 50-ton press, plasma cutter etc at my disposal. Once this box goes on, the rear leaf springs are getting tossed and I'll be doing a 5 link with airbags and then the 7.3 and ZF 6 speed are coming out in favor of a 94-97 Cummins and either an NV5600 or an Allison 3000. I bought this truck as a platform to build my dream tow rig on. I'm more than willing to put the time and work (not to mention money) into this thing to get it where I want it.

If I bought this truck because of the payload capacity then I would leave the deck on it but I wanted a 450 or 550 for the towing capacity. I work in new home construction and most of the sites I work on are terrible to get around in and that's the reason I'm so hell bent on a 7 foot box (more maneverable on site). I wanted an x cab short so with the crew cab I'm already long than I had wanted.

I'll post some pics once I get started on it

 

I know all about construction sites I haul debris away from sites plus I deliver small amounts (2-2.5 yards) or sand and gravel. Some of these places have driveways where I have to back from the public paved road to the house site. The farthest I have had to back into a house site is couple thousand feet maybe more the driveways with the over 1km long dirt roads have to have room to turn around.

The access road is usually just 8'6" wide with trees and brush lining either side of the driveway you have to watch the fenders or a tree may take it off. I know I have removed bark from people trees with the sides of my deck because its such a tight fit. The road usually snakes around and inbetween the big trees 36" diameter doug firs so you only have inches of clearance.

Some roads are a one shot deal once you start backing down you have to try make it in one pass as you will have a h*** of a time trying to pull forward because they are steep and loose gravel. Some of the driveways I have had to back down the truck just starts sliding so no touching the brakes.

There are alot of house sites where I can barely turn my F-450 around which is a regular cab with a 12' deck. A 100 point turn isn't uncommon and driving the truck into the bush or into uncleared areas to try get turned around.

For most places where I never been too I will walk the driveway which could be 1/4 of a mile long to see if there is room to turn around. You drive down some of these places there is no way you can back out. Most construction sites have so many sub contractor vehicals on site its like backing through a maze of vehicals. There is always a fight who can get closest to the front door usually the clean up contractor wins (me). They all grumble and groan they have to move their trucks out of the way the electricians and plumbers are the worst

Anyhow the worst sites I hate is the ones with the access roads that have switch backs where you can only turn so far back up turn some more back up then drive straight ahead. Some of the turns are really tight where you have to put one of the front tires into the weeds so the paint on the fenders suffer some brush scratches.

I would hate to try get a crew cab truck into the sites I go it would never fit plus there is way too much exposed sheet metal to get dented.

All I can say is you gotta have good judgement and be good with mirrors especially when your trying to squeeze a 8' wide truck through a 8' 2" wide spot

Good Luck with the project