What I've learned that there is almost nothing that will guarantee results. Its usually a mix of experimentation that yields results. For that reason I try to keep all of my mods as cheap as possible. This helps in 2 ways:

1. Low cost means less $ lost if the mod doesn't work.

2. Lower cost will equal a higher payback ratio if it does work.

Does it have blocks between the springs and axles?

An idea that is low cost but a lot of work is one used on Rangers to lower the rear and improve stability. Remount the axles on top of the leaf springs, instead of under.

That's a good one. I didn't know it was possible on trucks. I did it on two trailers, lowering one and raising the other.

Well, I took everybody's advice and left the Superduty at the same height...... bought a pair of new Monroe shocks for the rear. Put them on myself too. I usually have the dealer do the work. It felt good getting my hands dirty again. And save a few bucks.