Im not sure how to make this out, but some insite on this subject would help out. From my understanding a early 90s F-250s springs measure 2.5" as do a 99-04 Superduty. if this is so then the springs should be interchangeable???? putting superduty springs on a early model 250. or is it the length of the springs that will not allow this? does this also not work with lift springs and add a leafs?
If it is not would the spring mounts be the only thing needed to be changed to make it work? Or am i looking to much into it to be as simple as the springs can be changed out.

I believe the SD springs are longer, and you will must do a shackle reversal to make it happen.

Not sure though.

Im still running the ubber-craptastic leaf-sprung TTB :flipoff2:

same here for the TTB thats why i am looking to see if i get a solid front end with springs if it was compatable.
thanks for the info on the shackle reversal something i need to look into now

The leafs are both 3" wide. The 99up are longer and have the centerpin in a different location. They wont work. They will however work in a 73-79 F-250/350 4wd.

we put 6" superduty springs on a 94 f350 and it lifted it enough to completely clear 39" Boggers. the guy drove it all the time, never complained about anything hitting. axle appeared roughly centered in the wheel well. FWIW

same here for the TTB thats why i am looking to see if i get a solid front end with springs if it was compatable.
thanks for the info on the shackle reversal something i need to look into now after reading this, know that the spring perches are different widths, indicating different width frames. The superduty front under an older truck will require the spring perch on the driver side to be ground into about an inch or so for the spring to sit straight vertically.