rear end interchange between what years?

[bwc302]

Can anyone tell me what year rear ends will interchange with our 67 - 72 1/2 ton F100's? (Will those up through 79 work, 9" is what I have but I know there or D60's and others)

Thanks,

Bobby

[FORDification]

If you're talking about the entire assembly, you can only use '65-'72. The '73-'79 F100 and F150 frames got 4" wider, so the spring perches had to be relocated out 2" on each side for those years. Virtually all 1/2-tons had 9" Ford rearends, though you could special-order a 5-lug Dana 60, but they're not that easy to find.

You can use the '73-up rearend if you're willing to relocate the spring perches. Not only would you get a rearend that was several inches wider (for better stability, and will finally make the rear wheels track behind the fronts), but you'll most likely also get stronger 31-spline axles, as opposed to the slightly-weaker 28-spline that our trucks had.

[bwc302]

Thanks Keith, that is exactly what I was wanting to know.

So the spring perches on the 73 - 79 would need to be moved inward by 2" on each side to match up with the 65 - 72 models if I followed correctly.

Bobby

[FORDification]

That is correct....though it's a rough measurement. You should get a more exact measurement from your bumpside rearend before actually doing any welding, just to be safe.