Some vans have reverse cut gears in the steering box too. That can keep you from needing to mount the box so far forward on the frame.
I swapped a solid axle into an S10 once, but doing so reversed the steering. So we just snagged an Astro box that was externally identical but internally reversed. Threw in a 76 Econoline pitman arm too, I believe. It may have had four skip splines already too, if I remember correctly.
I think the same swap ability exists with the full sized models. It may be worth looking into.
