Quick back ground. I'm putting a LWB 72 F-100 2WD Body on a 74 F-250 4WD frame "Highboy."

The 72 is still all together while the 74 Highboy frame gets cleaned and painted.

The 74 Highboy frame is a bare rolling frame - no body on it. I do not have any of the 74 body.

Known Information:
From the rear of the cab forward the frames are the same between 67-72 & 73-79. There where some changes under the bed on 73-79's noted below.

67-72 Wheel base is 131 inches (Long Bed)

73-79 Wheel base is 133 inches (Long Bed)

67-72 F-100, F-250 2WD & 4WD frame width rear of cab 33.5 inches

73 - through early 77 F-250 4WD frame width rear of cab 33.5 inches

Late 77-79 F-250 4WD frame width rear of cab 37.5 inches

73-79 F-100, F-250 2WD frame width rear of cab 37.5 inches

73-79 F-100 4WD frame widths ??? (doesn't pertain to me but may help others)

Questions:
Basically, I'm trying to figure out if the 74 frame bed bolt holes will match up with the 72 bed bolt holes?

If so, does this put the wheel centered in the wheel well leaving a 2 inch wider gap between the cab and bed?

I'm trying to figure out if I need to move the axle forward on the frame (before paint) or move the bed forward (drill new bed bolt holes in the frame).

I have added some extra information above for those who might find it useful.

I have searched for this information for several days without conclusive results. I hope to hear from those who have done this as the frame goes to the media blaster next week!

Thanks for your input.

 

Red, In 73 there was 4in added to the rear of the cab behind the mount holes. Even though the cabs are longer after 73 the mount points are the same. The chassis area under the bed was widened to allow the rear track to match the front, that was widened in 65 when the twin I-beam was introduced. "The reason why".

I don't roll with the 4wd so I was unaware that the later 4wd was not as wide as the 2wd.

You are going to be faced with fitting issues, and I suggest that you dry fit things. Don't know if you are willing to cut the chassis to better aliegn the rear wheels in the opening, or if you can live with the difference.

I would suggest welding plates to the chassis and use the exesting bed bolt holes.


John

 

1st, 2X John on welding plates to the 74 frame to bolt the bed down. From here I got an idea. As John said if you bolt the cab in it's place and the bed with the wheel opening centered over the rear tires you will end up with approx. 4" gap between the cab and bed. SO WHY NOT EXTEND THE BACK OF THE CAB TO MATCH? Kinda like a semi Supercab. I'm not saying it would be easy but if I had welding skills I'd rather create more space behind the seat rather than cut and Z the frame shorter. Find a donor cab,cut the back of it off long,cut the back of your cab off short, and weld it back together. I've seen threads where guys cut a section out of a L.B to make it a S.B and weld it back together. If they can weld bedsides back together it ought to be possible to weld cab corners and roofs back together. Low heat. Am I missing something guys?

 

Thanks for the replies, but there is no need to weld brackets onto a 73 - early 77 F-250 4WD frame as they are the same width as a 67-72.

I will reiterate my questions with a slight edit.

 

Yes, it will bolt on and leave a gap using the factory holes.

 

That is half of the equation.

Should I assume this will put the rear wheels centered in the wheel well of the 72 bed?

 

Correct on what Jared said, but it is not the width, for the hole issue it is the length. One other concern the hole spacings may not be the same.

You need to do a dry run to fit or mount the cab & front clip then work with the bed.


John

 

The hole spacing is the same, the wheelwells will be centered leaving a gap between the cab and bed.

 

Thanks Ford_Six. That is the conclusion I had come to after a lot of searching and reading but nothing I read had clearly stated such.

Looks like both the bed and axle will be moving forward on this project.

 

Red, I apologize if I told you something wrong, I was pretty sure that a missalignment has occured prior but I can be mistaken. Please let us know how well it fits once you can get the bed on the chassis and lined up.



John