I’m looking to swap my rear end on my flat bed 74 F-250 to a dually 1 ton rear.
I believe I have the room for it under the 82” wide bed
the truck is a 4 speed manual that I usually start in 2nd so wouldn’t mind a higher gear ratio and the 1 ton springs if you think I need them. What do you guys recommend that would bolt right up to my frame.
the frame measures is 37” from outside to outside.

I think ive read where dually 1 tons had 34” frames for that year.
Man other option is the dually adapters bud I’d be losing the higher gear option.

what do you guys think.
yall seem pretty savvy about these kind of things.

 

F350's with DRW thru 1979 were only available as a Cab & Chassis or with factory installed flat and stake beds.

All 1963/84 F350's have a Dana 70 rear axle (except 1979 F350 4WD), but you'll need one from a 1973/79 with DRW

You will also need all the rear brake parts including the drums and the wheels. Be aware that the left rear wheel uses L/H lug nuts/studs.

Plus with the narrow rear frame, the spring perches and shock mounts will be located in a different place than your F250.

1973/79 Dana 70 rear axle ratios: 3.73 / 4.10 / 4.56 / 4.88

Unless you need DRW, I'd say forget it. It's going to be very labor intensive, plus what the parts will cost and where will you find them all?

btw: I assume you're aware that your 1974 F250 has a 1978/79 grille and front bumper.

 

[i appreciate all the great information it don’t sound like you’re any dummy when it comes to these trucks.
Mom hoping to find a simple swap out from a wrecking yard. Breaks springs and all. Pick and pull is pretty reasonable especially when the tool kit rewards have 1/2 off days.
The breaks and wheels are gonna need replaced anyway and would be nice to have upgrades for stopping power.
I’m considering using this truck to pull a 30’ fifth wheel car trailer on occasion. The 390 has plenty of torque for it. thinking I have 4:10 gears in the ole truck now.
What ratio would you recommend if I’m still hauling but want a little better mileage or highway speed.
Also would a newer 1 ton rearend and dually combo work? Like off a 90 or newer ford?


? QUOTE=NumberDummy;18701892]F350's with DRW thru 1979 were only available as a Cab & Chassis or with factory installed flat and stake beds.

All 1963/84 F350's have a Dana 70 rear axle (except 1979 F350 4WD), but you'll need one from a 1973/79 with DRW

You will also need all the rear brake parts including the drums and the wheels. Be aware that the left rear wheel uses L/H lug nuts/studs.

Plus with the narrow rear frame, the spring perches and shock mounts will be located in a different place than your F250.

1973/79 Dana 70 rear axle ratios: 3.73 / 4.10 / 4.56 / 4.88

Unless you need DRW, I'd say forget it. It's going to be very labor intensive, plus what the parts will cost and where will you find them all?

btw: I assume you're aware that your 1974 F250 has a 1978/79 grille and front bumper.[/QUOTE]

 

You know just because you put a 1 ton duel wheel axle and maybe springs does not make your truck a 1 ton.
Do you know what the load & pulling cap. is for the truck as that is what DOT will go by when pulled over or scaled and you will when pulling that 30' car trailer now days.
For the load & cap. you will need to know what the pin weight is of the 5th wheel and the total weight for pulling.

I used a 76 E350 460/C6 to pull a bumper pull 2 car open deck trailer, was about 30' also, and it did the job just fine with the single rear wheels but it was a 350 truck not a 250.
I did used a 70's F250 4x4 with a 400/T18? granny low to pull the same trailer but was only 20 miles but it do it fine also.

I would run the numbers and if with in the limits of the truck for DOT, yours and everyone else safety then move forward to setup the truck to pull the 5th wheel trailer.
Don't over look the weight rating of the tires on the truck.
Just my .02
Dave ----

 

You can use any dually axle from other makes but keep in mind the eccentric rims will be different. I've discovered they are different for every make. Dodge is even different, unlike what I have been told.

Best to find a Ford Dana 70.

Also consider it may look a tad odd running a dually rear with single rear front. You can add adapters but it will wear a f250 front end out faster than a f350 due to kingpin size / bearings / such.

 

You are not getting a DRW axle to fit under the frame it's just not happening. The drums hit the springs.

 

Oh contrair... You mean that he is not going to find a 73-79 Dana 70 to fit. And yes, it slipped my mind that they wont. And neither will any cab and chassis rear end from any other 1 ton truck.

BUT! On the other hand any Dana 70, Dana 70/80 hybrid or Dana 80 from a later model Ford, Dodge or Chevrolet will fit easily from another DRW truck that came with a bed for everybody went to a gas tank in the rear soon after our dinosaurs. I have a few different flavors in my possession to prove it. And have that option in my pocket for future builds. But the tires will most likely stick out. And the only things that needs changed is the spring mount and shock hanger locations and most likely the tail end of the drive-shaft u-joint for they went bigger. There's aftermarket yokes in every flavor as well if you wanted to correct it in that direction.