Rack and Pinion conversion from a late model truck

[69GMC2004]

I'm going to be doing a power steering conversion and was contemplating going rack and pinion. I'm wondering if anyone has used a rack and pinion form a late model truck in their 67-72?

Reason I'm considering this is because I already have a truck with the rack and pinion in it, that truck is the donor for engine and hydro boost unit I hope to use. I imagine it would be simpler to use all the components that were designed together.

Secondary question. For those running rack and pinion set ups with an LS engine, what have you found to work for headers/steering shaft combination?