Just like the title says. My 1999 F-250 4x4 has 5.25-5.5 inch rear blocks. And compared to my cousins 2000 F-250 I have one extra spring and some traction bar looking spring. My U-bolts are 19 inches long and have 2.5 inches sticking up above the nut.
From what I have read the 99 F-250 had a 4 inch rear block factory and that's what I have to put back in. So I think I'll be going back to factory height plus the 2 extra springs.
I think I need around a 16 inch long u-bolt. I could probably do 15.5 to 16.5. 15.5 might be close though. I know they are 5/8 diameter and I think 3 5/8 inside width. I've checked Summit, Jegs, and Google and came up empty. I'm sure theres somewhere that specializes in this stuff but I'm new to super dutys and don't really know where to look. Anyone?

 

Go to thesuspensionking.com, they will custome build u-bolts to your specifications & start at $6 a piece.