Re: Oc Craigsfist, Deaver springs for SuperDuty.
F-series have a slightly longer eye-to-eye length than the E-series leafs, at least stock. I tried some Superduty spring on my van and there was a little rubbing with the spring and shackle mount. That running might be worse on a spring with even more arch. It also located the axle rearward about an inch too far (which didn't seem to hurt anything but chains clearance in the finder).
But for that price.... might be worth it to re-locate the rear shackles. Just grind away some rivets, and bolt them up a little rearward....
2000 E450 dually V10 wagon