okay guys. I have a 1990 f250 xlt lariat 7.3 idi 4wd and i just bought a 1984 f350 with a really nice flatbed with 4.10s same as my truck>. so im gona swap the bed and axle I was reading a different forum and some one said that the f350 axle out of a 1987 or before will not work in the 90s model i dnt get y becuase its the same width as my 1990 rear end on the leaf spring any idea? ill post pics in morning

 

so your looking to do a dually conversion with a 1984 rear axle which is what? the D70?
is the '84 donor an f350 pickup or cab n chassis?
not sure why the D70 wouldn't work (short of not having a abs sensor,but big deal.) just as long as it's approx 59" between brake backing plates.
maybe there's some odd reason why someone says it won't work for your '90.i don't know what it would be.

 

if the 84 is a cab and chassis then the spring perches will be narrower than the f250

 

The 84 has no ABS sensor on the axle, so this will throw the ABS light on. And like others have said, if the 84 is acab-n-chassi, the axle will Not bolt in place of the F250 axle and the bed will Not bolt on either

 

yea its the same width everything measures up the same i dont care about the abs light its allways on anyway. I was just confused on y it whould not work but i guess whoever that is was wrong. here's some pics i got the complete 84 with 44000 original miles for 400 dollars its got the 460. looks like some ones gona buy engine and tranny from me for 500 dollars heres a pic!!

 

sorry here u go this is my truck that im installing the flatbed on
and here the parts truck for the flatbed then my gf soon to be wife{ has a 1985 6.9 4x4 so im gona use some parts off of it.
what u guys think

 

then it won't work.
though in the pic, it looks like a pretty wide stance to me. perhaps you didn't measure properly?
you should start over.
list the measurement between spring hangers and between backing plates on the '84.what do you get exactly?
measure the frame width and or list the vin for the '84,what do you get exactly?
i ran into this issue with a salvage yard,and it was like pulling teeth with them too.
it doesn't need to be this hard.if you want to know,get out the tape measure and provide real numbers,and or the vin of the '84.



in order to get dual wheels to fit on your f250 (or a srw f350 pickup) you would need a much wider axle.not the one that measures close to your current srw f350/f250 sterling 10.25 axle.
if you do get a close measurement between backing plates as you do your current srw axle in the '90,this means that f350 donor is a cab n chassis rear,and it is of no use to you at all.
the reason why it can fit dually rims,is because the frame is narrower.....if your comment above is 100% accurate.

with all that said,you can just run arrowcraft magnum spacers on the rear to fit dually rims on your current srw '90 and be done.but they cost $ of course.

you should also know that there are only two advantages of running DRW vs SRW.
payload
stability
(and i suppose a bit extra safety in the event of a flat while towing)
with everything else being a con,for example,but not limited to;
reduced economy (i took a 1.5-2 mpg hit.)
drastically reduced traction (where my truck once went without issue in 4wd,i wouldn't even dream about taking now as drw.)
more tires to buy,rotate,balance etc.
if there is actually a need for a drw truck there is no vs a srw.you won't think twice.it's so far worth it,it's not funny.if the need isn't there,its one very,very,very costly mistake imho, because it increases total cost of ownership greatly.it's not just in initial part swap price of the parts,even in this case,they might be free (besides new u-bolts) ....there's still a large price to pay.just the same as lifting a truck and running cool looking mudders.way more $ involved than just the lift,rims and rubber.
cost of ownership for a basic srw f150 today sucks,let's face it.

 

Just measure the frame. If it is a 34'' frame on the dually it won't work. If it is a 38" frame it will. I highly doubt it is the same width. And you can't just put the rims on your axle they will hit the springs and require about 3" of spacer per side to fit.

 

I was meaning the the leaf perches are the same.
the overall width of the dually axle is way wider then my srw axle and yes its a dana 70.
and I hate flatbeds with srw haha.. I tow a lot in the past three days ive towed a 96 dodge cummins and this 84 f350 and a 9000lbs tractor.
tonight im geting a 90 chevy to part out. my older truck has drw on it that i installed.
I had a detroit 453 t in it. Its my baby but i had to tear it down to start fixing some rust on the cab. here a pic

 

97 tugger is right. you better break out the tape measure AGAIN.

A pickup frame is 37-3/4" a Cab-n-chassis is 34"
Ford Never made a 4wd F350 Pickup, only cab-n-chassis, so my bet is that is a Cab-n-chassis which means the rear spring perches are TOO narrow to fit on your Pickup

 

have any of yall actually looked at that pic its 2wd and rear axle looks alot wider than the front meaning its prob not a cab and chassis
and brad check ur measurments ur saying a cab and chassis is 1/4" wider ???

 

Cab and chassis are 34" he must of messed it up.

 

There I corrected it. And the rear axle will be wider, it a DUALLY.

But you are correct, the pic he shows is of a 2wd, but he talks about his GF truck that is 4wd

 

yea im gona look for a new axle tomorrow i pulled the diff cover off it has 3-54 gears and i need 410s i dnt wanna swap gear cheaper just to find a complete dually rear end or ill just buy some spacers. anyone needs some parts are the whole 84? all i wanted was the flatbed and the seat and i stuck a okay seat back in it

 

Spacers will be cheaper, about 200. A dually PICKUP axle is gonna be 500+