I'm sure this has been asked before but I couldn't find it.
I have a 1978 F250 SRW reg cab 4x4 w/3.54 gears that Needs at least a 4.10 DRW for the rear, I know I'll need 2 spare tires and the rear ratio won't match the front....that really don't matter.
The question is what Frames if any are compatable with my '78 4x4?
If I find a F350 DRW that is 2wd will it have the same width frame?
This truck is a farm truck that pulls a 18,000lb gooseneck, power isn't the problem, It has a mildly built 429 that is 365 HP, its just too high geared to pull that much weight @ 55, also DRW for the weight safety.
Please help, Thanks in advance.



p.s.
My old '79 f250 w3.54s had a T18, but this thing has a NP435, Why is 3rd and 4th so freaking far away from each other? This old '78, ya wind it to nearly 4,000 in third then it dies in forth at 55mph. I dont remeber my '79 being like that, maybe it was?

 

I too am thinking of doing this to my 78 F250 4x4 Camper Special. I am in the early, early stages of planning. I have a friend a couple of miles away who has a 78 (or at least the title/drivers door was) F350 2WD dually that I could have pretty cheap. I went and looked at it in fall only to find my 4x4 frame a few inches more in overall width. I think it was something like 34" compared to 38" or something like that. Also the 2wd dually had narrower leaf packs and had shorter length. I think if the leaf springs were moved outward on the dually axle to clear my 4x4 frame they would be tight against the backing plates plus I'm not sure if the inner tire would rub on the leaf pack. I have seen a handful of late 70's dually 4x4's on this site but not much discussion on the conversions. I'm anxious to see if we can be "enlightened" by our FTE friends!

 

Also, I thought I remember someone telling me you could get 70's Ford dually rear axles (Dana 70?) in a narrow or wide width but I'm not sure if there is any truth to that.

 

ok, why not get yourself a set of dually rims and go to the junkyard and find a d60 rear ring and pinion in the 4.10 ratio to put in your old axle.....and while your at it find the front ring and pinion, what good is a 4x4 if you cant use it....

 

look for a 80's or 90's dually pickup truck with a bed on it, these should be the full width rear, and bolt onto your truck with no mods. And if you get a 10.25 ford rear you can remove the brake drums without tearing the axle apart.

 

The reason why not to change R/P is I don't want to do a setup on one of those Mickeymouse rearends, I can use 4x4 IF I am stuck as there will be enough slip on the slimey crap i'm stuck in. I did a rearend swap on a 94 f150 3.31 frt 3.54 rr It worked for what I needed it for...I still would like duals, I have a Flatbed so width that way is ok, I just need the darn springs to line up!

 

I just un duallized my '77 crew cab, don't quote me on it but i believe that the diff are wider from the perches outward and they are the same as far as year specific as to truck application, but I did notice that the '77 has 2 1/4" wide springs and my 78's and 79's have 3" wide, but the rears are d60's, BE CAREFUL on what year rear diff you go w/, because the budd rims will not interchange between the years. PM me for detailed pics and some additional info.
here is a pic w/ 33" tire on d/s and budds on p/s

 

mickeymouse rearends??? granted a d60 is nowhere near unbreakable but for what you are doing i think it would be ok....hell i have one with 4.88 gears detroit and 39.5x15 swampers on stock 30 spline axles, with no problems....yet

 

Oh...... the things that my mickeymouse rearends have lived through and can tell about, some GREAT war stories!!!

 

I already have a Dana 60 and if I understand you right you're saying just go to the junkyard and pick up some dually rims and presto, a dually. I'm not 100% but I think I would at the very least need longer studs and also are dually rim pilot holes compatible with D60 hubs. How much will the inner rim hang over the backing plate?

 

Have you done this hillbillyk? I kinda like the idea of an 80's/90's 10.25 under there. I heard they are pretty tough. I bet they are easier to find too! Bolting on with no mods sounds too good to be true.

 

here is a pic of proper dual wheel rim for a 77 d60, notice the raised and recessed area at the lug nut surface area, this is what 'locks/aligns' the 2 rims to each other, my 77 crew cab that I removed the dual wheel rims from the rear d60 had no alignment pin and I just put the 33" tires on it w/out any modifications/problems. Only difference being that the rear whell stud are a little larger in dia. vs the front d60

these rims are specific to the older d60's and WILL not interchange w/ the sterlings, I have that on my 88 f350

 

Okay, I just learned something. I thought factory duallies in 70's Ford were all Dana 70s. If I find these rims and get longer studs that's all I need? Do you know what the width is from outside of wheel to wheel? I wanna install a 7' wide dump box and don't want the tires to stick out.

 

The truck I have has a D44 front and a D60 Rear, Mickymouse = rear cover type rearend....a 9" is a "Real" rearend in that you are NOT doing the "setup" under the truck, but on the bench!

My dream rearend would be a full floating 9" w/8 lug big disc brakes...just think of the ratios you could have, 2.5 to 7.00
The 2.5 would work nice in a future project!

 

If you get these rims you will need to get the "LARGER DIAMETER" studs, the doo not appear to be any longer than those used by the srw, see pic.

I recall some one mentioning in another post that the d70 are usually in the later model 70's 350 2wd, which is what I have in my 78 f350 2wd crew cab. I don't know of the neasurement for the width or how much it will stick out and I realize that the pic is not really that informative...sorry, but the tires are broke down off the rims and the 33's are in place. I do know that the 88 f350 4x4 mason dump that has a sterling 10.25 in it is wider than most other sterling and I have a 6' wide inside bed width, plus the extra width at the base of the dump. That becomes a whole other issue on what and where you are hauling as far as the necessity for the wider rear axle, my buddies 78 f350 mason dump has the narrower rear axle and he has no problem but I can see that it isn't as stable as mine, but it works! Here is another pic of dual wheel on d60

Also when I checked w/ my local parts store the larger wheel/lug studs were factory for my 77 f250 4x4 crew d60 rear, I hope this helps your decision