The rearward-placed rear axle is from using F250 springs. The eye to eye length is a little different. They work, but this is what happens. It's fine for a 4x4, and it worked fine with my 2WD, but it did make me little nervous that'd I'd someday pop the driveline out of the tranny and pole-vault the back end. So I went back to E-series springs.
Great work BTW!
I tried the ratchet strap trick once to no avail. Finally used some carb cleaner to seat the bead. First time, it worked, then once it cooled, sucked the bead back off. 2nd time, I was quicker with the compressed air.
BTW - Every time I've though about going back to singles, I think of stories like this. Besides the spare on the back, I always have 2 more built in...
2000 E450 dually V10 wagon