Sswap, if my strained memory serves, I think you will find the combo you are looking for under a Mark V Lincoln. I stripped one down last winter, but I cannot recall for sure where the springs ran on the frame. The Lincoln has a 9" rear end with disc brakes, but it is pretty wide--62-64".
I am looking to do some horse trading with a friend that has a rear end from a mid 60's F**d pickup, which (if my measurements are correct) is 60" wide and will fit nicely. All I have to do is switch the caliper assemblies over to the narrower rear.
