I've done a search, and cant find anything that says WHY the 67-77 F250 4x4 frame is 4" narrower than the other trucks of those years. Why did Ford do this? Was there a purpose, or is it like that "just because"?

 

Unlike the 150 (2x4 and 4x4) and the F250 (2x4) that got a total redesign in 73, the Highboy frame was a holdover from the previous model design (67 - 72).
As to why its not the same width? Who knows.. trying to get as much room in the wheel wells for bigger tires? invent a time machine and we'll go back and ask the designer..

 

But why was the 67-72 Highboy frame narrow also? I guess I could ask in the 67-72 Forums.

 

It looks like it would allow more flex for the rear axle but I don't picture Ford being very concerned with that in the 50's and 60's. Good question though, they obviously went out of their way to narrow the rear and not the front of the frame.

 

they did have optional side mount saddle tanks back them...????? maybe?

 

Well think of it this way: The highboy frame isn't really narrower . . . it just doesn't flare out toward the rear. The width at the front is the same as all the other trucks of that era but the lighter 4x4's and 2wd truck frames flared out under the cab (just like the 78/79 F250's) to be 4" wider at the rear. Highboys use a ladder frame, rails that run straight front to back with crossmembers to tie it all together. My guess would be that it was a stronger frame design at the time than the flared frame rails and this is why it was used on the 3/4 ton 4x4's.

 

That answers it then. I was thinking the early frames were wider at the front and narrowed behind the cab, and the newer trucks were just wider the full length. It's exactly opposite of what I had in my head - sorry Trey.

 

The reason for the narrow frame in the rear is because they had to be narrower if you wanted to fit a dually rear axle on it.

 

they did it so you couldnt buy any aftermarket parts for it like gas tanks. like you can with the 1/2 tons or the 78 79 3/4 and 1 tons, thats why i just bought a 79 1 ton for the frame and running gear going to put my body on it. with a alot of modifications to it of course like shinny lug nuts and those valve stem caps that light up . its going to be pimp

 

If this is true then how were they running dually axles on the 2wd trucks of that era that had the wider frames? The inner tire still sits in the same place as it would with a single rear wheel. Personally I don't think dually axles had anything to do with it but I've been wrong before.

 

maybe they thought it was a good idea

 

Ivan already hit the nail on the head several posts up. It was a design already in use, it was strong and it was financially viable for Ford to continue to use it on the 3/4 ton trucks. Once in a great while I pull my head out to see if the sun still shines - kind of like a ground hog.

 

i went and got a window installed in my beel button so i can see when my head is up there.

 

The 67-72 trucks all have the same width frame rails 1/2 ton to 1 ton 2 or 4 wheel drive didin't matter. In 73 ford widened the 2wd pickup and 1/2 ton 4x4 frame in the rear by about 5 inches BUT!!! All the heavy 73 and later trucks and f-250 4x4's stayed with the narrow frame and 40" spring spacing. Factory cab chassis dually trucks and super camper special f-350 trucks had the narrow 40" spring spacing. My best guess as to why they would do this is for strength as Ivan said. A frame that's straight from front to back is alot stronger than one that is straight from the front to the back of the cab and then begins to widen out. Just my personal experience here, but I've seen a few 73 to 79 2wd f-250's with cracked frames from being overloaded. two of the broken frames were on the driver side rail just aft of the rear cab mount crossmember the other was at the steering box. I have yet to see a 67-72 truck with a cracked frame or any f-250 4x4 with a frame crack that had anything to do with being overloaded.

We all know the real reason why ford did this was to drive good 73 to 77 f-250 4x4 bed prices to rediculous levels. Us 67-72 guys have it pretty easy with all the beds interchanging. 73-77 guys got 30 spline rear axles, 205 cases, power steering and power brakes though so I guess we're even.

Dustin

 

Yeah, it was my understanding the 350 had the narrower frame also, so the highboy was really just an F350 frame.