personally, I would not use the rack on the I beam axle. maybe the toyota box, moved forward a bit, with a custom pitman arm? maybe a taller steering box with a bottom outlet pitman arm and a longer pitman shaft tube, that would place the box a little higher on the frame so maybe miss a few engine items. I have worked on a few old ford 1/2 and 3/4 tons from the '70's with a long pitman shaft steering box. maybe something like that could be used? it would need to go inside the frame possibly in front of the starter? pitman arm exits the side of the frame? I dunno, just spit-balling. maybe a trip to pick n pull for a look see what might work.
https://www.amazon.com/Power-Steerin.../dp/B01MSJKHWI