Building a 75 high boy. I just came across a 78, and willing to buy it for parts. But need to know if the axels and the box and such will work on the 75? I know the 76 would work but wasn't to sure about the 78. Would like to call the guy today and pick it up tomorrow.
Any answers would be helpful
Thanks!!

 

IIRC, the rear frame width is narrower on the 75 than the 78.

 

So the box and rear axel would not work on the 75

 

So the box and rear axel would not work on the 75

 

That's what i would deduce.... It's not a "bolt" on affair for the bed since drilling is required. I have no idea what needs to be done.

From the Highboy Info Compilation: https://www.ford-trucks.com/forums/9...mpilation.html

KNOW YOUR TRUCK!!!

################################################## #########################
"# Highboy Frames #
################################################## #########################

Highboys have a unique frame, not shared with other trucks. Like the F-350
frame, all Highboys have a narrow frame, which is 33.5-inches wide. Fifth
generation (1967-1972) F-series trucks had narrow frames as well. Sixth
generation (1973-1979) F-series trucks had wider 37.5-inch rear frame
rails, except for the 1973-1977.5 Highboy frame and the 1973-1979 F-350
with 139-inch wheelbase. This frame rail width is measured directly
behind the rear bumper, from outside of rail to outside of rail. The F-350
frame was narrowed for duallies. The Highboy frame does not bend to the
left or right (unlike the other F-100, F-150, or F-250 frames), though it
does bend up and down to accommodate the cab. A front crossmember,
positioned just below the front bumper and visible while standing in front
of the truck, separates the Highboy frame from the bumpside F-350 frame.
No other truck had this crossmember. Since Highboys have a frame that is
different from other F-series trucks, Highboys require different beds than
other F-series. The Highboy frame was never used on another truck."

################################################## #########################
# Highboy Axles #
################################################## #########################

Front axles were an 8-lug low-pinion Dana 44 (1967-1977.5), 8-lug
low-pinion Dana 44HD (1969-1975), or 8-lug low-pinion Dana 60 (1973-1975,
Crew Cab Highboys only). There were no high-pinion front axles in
Highboys, although high-pinion front axles are preferable to low-pinion
front axles. The Highboy front axles were a closed-knuckle design from
1967-1975, and open-knuckle design in 1976-1977.5. The open-knuckle
design is preferable. Many Highboy owners replace their low-pinion front
axles with a high pinion 1977.5-1979 Dana 44, or better yet, the 1979
high-pinion HD Dana 60 with 35-spline inner shafts and 30-spline outer
shafts.

Rear axles were an 8-lug full-floating Dana 60 with 16 splines (1967-1975)
or 30 splines (1967-1977.5), but both were the same 1-5/16" diameter. It
is common for those with the 16-spline Dana 60's to replace them with a
Dana 70, GM 10.5" 14-bolt, or other rear-end.

In 1976, HD external hubs became standard.

All Highboys had 4.10:1 gear ratios.

################

 

Bed will work, you will just have to drill holes in the new bed to match your original narrow frame bolt holes, OR weld tabs on the frame to use the existing wider frame original bed holes.

And probably do some fuel filler hose mods? To get the newer gas flap bed to work with your exposed filler neck tube.

Axle should work...should??? I'd just tape measure the old axle leaf spring pad overall width and the newer axle overall leaf spring pad width.

 

whats wrong with your rear axle.75 30 spline dana 60.Front axle direct swap dana 44 or 60..drive shaft difference front.Have to drill new holes for bed for existing bolt layout and add spacers for strength when tightening it down (compression)

 

nothing is wrong with my rear axel. its still a really good axel. but what about using 78 axels plus its transfer case? would that be worth it? or would it be better to just use the 75 rear axel and transfer case? and just use the 78 front axel?
just a thought.
I do plan on using the motor out of it. its 460 sounds and runs like a dream.

 

Read this...https://www.ford-trucks.com/forums/9...storation.html

I did the exact swap. Have fun!!!!

 

How was it? Worth the swap? Did you use the transfer case??