Re: Lifting a 2WD Van, part # 999???
I am used to coil spring spacers in the Jeep world, however we have always used them on TOP of the spring, as they fit over the bump stop tube. Somehow that seems more stable then the add a thread used at the bottom, but it's just a guess. I would think there would be more options in different full-size rig heights and applications (meaning top of the coil spring) as they are a pretty simple piece over all.
The analogous piece in the back would be a lift block for the leaf springs.