Just set it up with the correct shackle angle on level ground using some 1.5" lift shackles with greasable bushings. Replace the rear spring eye bushings with greasable poly ones and your suspension will ride and flex great.
BTW Dodge vans use a rear spring thai is the same distance from the front eye to the center pin and is 2" longer from the center pin to the rear spring eye. This will correct your shackle angle but you will need to use boomerang shackles.
I tried the set-up you have pictured and it can unload in a panic stop and on side hills. Once I trashed them and corrected my shacle angle I had no more bad handing characteristics.
BTW Dodge vans use a rear spring thai is the same distance from the front eye to the center pin and is 2" longer from the center pin to the rear spring eye. This will correct your shackle angle but you will need to use boomerang shackles.
I tried the set-up you have pictured and it can unload in a panic stop and on side hills. Once I trashed them and corrected my shacle angle I had no more bad handing characteristics.
