Numbers dummy and MikeOoOoOo, you guys are smart you'll know the answer to this one. I'm selling my dually axle and front suspension less springs to another member. we found a conumdrum. He has a 79 f350 scab with a 37" wide frame. I have a 78 f350 160" wheelbase cab and chassis with a 34" wide frame. He just parted out a 76 f250 with a 34" wide frame. How come the measurements between the 350s are different yet the 250 he parted out is the same as my 350. Or does one of us have a problem reading #s. Will any parts from my chassis work on his or are we making life difficult for ourselves. Thank you for a response.
In case your wondering, I'm putting my 78 cab on a 89 frame. Was delayed on my project due to ticker, i think the brake and clutch conversion caused it, but I restarted it this week. 52 years old and I had to get permission to play with my toys.

 

Dual rear wheel F350's used the narrow frame, single rear wheel F350's used the wide frame
If the 76 F250 is 4WD (highboy) it also used the narrow frame.

 

I swapped everything (and I mean everything) from a 1976 F350 Crew to a frame off of a 1976 F250 Crew (so I could have a short box) when I restored mine and everything swapped over perfectly. I thought I read that in '78 they changed the F250's and F350's to a wider frame?

 

Thanks for the reply Mike, I figured you would know. After awhile a person picks up on who has the right answers. I've driven 1 ton duallies most of my life and have only had 1 half ton and that was 25+ years ago so I'm used to the 34" width. It's these half tons that throw me for a loop sometimes. They look the same but their not always the same. Have a good day.

 

some 2wd's used the narrow frame even though they were not cab and chassis duallies... I had a dana 70 out that was under the rear of super camper special that had the narrow frame.

 

I swapped the cab off my 78 f350 dually onto a 89 f350 dually because my 35 year certified mechanic brother said it would probably be easier than swapping the suspensions. Ive been taking measurements on the rear axles from both trucks this past week and none of them are the same except tire size. I wish my brother was more elaborate in his answers and advice, but at least I'm wise enough to know that if he has vague suggestions to follow them and figure out why as I go.

 

hi there I am the other member privateer is dealing with and yes this is weird the data plate on the door says a 75 f250 rear axle on the plate is 37 [dana 60 3.54 ratio] yet this truck has a 400m 4 speed with a dana 70 axle ?? [probably swapped in at an earlier date] and yes a 34" wide frame measured behind the rear axle the only thing I never looked for yet and I will do that tonight is if there is holes or mounts for front springs that may explain the frame width if it used to be a 4wd at least I think its a dana 70 is there ant positive way to tell a dana 60 to a 70? if it is a 70 I will probably hang on to it as it would fit my 79 s/c/s please advise thanks and privateer I will be down your way in about 10 days or so

 

p.s. heres another question did for ever make a f350 true duel wheel 1 ton in the supercab with a 155" wheelbase? that would be perfect but probably dreaming that I would ever find one

 

https://wastegate.net/mav/tech/dana60-70.html

 

Miottimouse, I remember seeing CN & CP crew cabs with duallies and a service box but never a scab. I also don't recall ever seeing a flat sided dentside with duallies. That was one of my first hurdles I checked out when I started this project. Because of the way I want to finish my truck, I've been looking at the tri 5 chevy fender. Miotti that axle I have is a dana 70 with 4.10s

 

In the 70s the DRW and SRW trucks used the same d70 rear. The DRW trucks always had the narrow frame rails. Thats how the inner wheel would clear. On a wide frame truck you have to have a rearend thats 72" WMS for the inner wheel to clear the springs. From what ive found through the years with the various trucks ive had is that the 73-79 f350 C&C trucks along with the SCS with the 140" wb had the narrow frames. Same as the 73-77.5 f-250 4wds (highboys). The crewcab longbeds also had the narrow frame. From what ive read on here all the supercabs had a wide frame regaurdless of year or configuration. On the crewcabs with the shortbed ive found both narrow and wide frame and that looks to be based on what year they were. The best way to check if you have a d70 is to check lug nut size. it will have 7/8 or larger while the d60 will be 13/16. Something else ive ran into is that some of the d70s had left hand threads on the passenger side.

 

left hand threads on the driver's side.... ask me how i know.

easiest way to check if it is a d70 is look for the "70" stamped on the passenger's side of the housing right next to the diff cover.

everything else above is correct AFAIK.

 

I wasnt sure which side but was thinking it was pass side for some reason. Its been awhile since ive had a ford version of a 70 here.

 

Back in me younger years on the farm the dana 60 was nicknamed 3/4 ton rear. The biggest truck I've seen them in is the 350 srw. If we came accross one at Martin's, we would look at the cover and if you see a 3/8" strip of third member casing on the bottom right of the cover. Then you had an axle you can put duallies on, a D70. If the cover is a perfect fit the you have a d60 and it won't bolt in to the 1 ton dually frame. Modifying it to fit in order to have a weaker axle goes against farmer logic. I came from a small farm town in Manitoba. We didn't have books for specs, we had Martin and his bone yard. He seemed to know what worked and what didn't.
Miotti, this truck I'm chasing down is starting to become a pita. It's there, worth what I'll pay him. Not much.

 

meborder lol that's funny about the left hand threads on the d/s let me guess you had a flat tire , needed to change it on the side of a highway , broke a nut turning the nuts to the left with a 3ft snipe thinking wtf and finaly figuring it out WRONG WAY bin there done that [lots of mutter mutter ## after the fact] at 54 years old I should have known that as a lot of the contractors that came in to the brick yard where I used to work at had those my 79 s/c has the dana 70 with left hand threads also any way I look at it I am going to have 1 rear tire sticking out past my box IF the wider duel wheel brake drum has enough clearance for the inside tire to the frame/spring and I am hoping I don't have to remove my air bag helper spring kit but that's why I have being looking for original parts for this duely swap due to minor cost compared to new adaptors,flat faced new style wheels etc. I will try to get some pics of that f250 with the 34" frame like I said realy weird never seen this before but it does have the 133" wheelbase as I measured it before loading onto my trailer and will get a better look at the rear end and will look for that "70" stamp I found a fellow in Edmonton that wants to take a shot at building me custom fiberglass fenders starting from the wheel arch lip to the race track moulding only and also keeping with the original wheel arch shape also so I can use the factory aluminum mouldings and if it does not work oh well I wont have a lot of cost tied into it other than driving to get these parts