Greetings, BuddyinAK. Sounds like you're going to have some fun up there in the tundra! All kidding aside, the two points you mention (steering and crossmember) will be your main points of interference. Since you are working on an AD truck, MANY have gone down this road before and you can benefit from their experiences. In a nutshell, you need to remove the bellhousing crossmember and replace it with late model engine/trans mounting crossmembers. then you move the steering box outwards from the frame about 1 1/4'-1 1/2" and heat and bend the pitman arm back in.
There is an article floating around on the net entitled "V-8 juice for your Stovebolt." It was authored by Pat Ganahl for StreetRodder or Rod & Custom back in the mid seventies, and covers this exact swap in some detail. The good news is that you can buy the crossmembers premade in the aftermarket (Chevy Duty is one supplier) for a reasonable sum. The spacer bracket for the steering box looks pretty simple to build and you should be able to have your pitman arm heated/bent safely by a competent technician at a reputable local frontend or machine shop. I'm sorry I don't have a link to this article, just type the title into your search engine and you should be good to go.
Hope this is of some help to you.
Regards,
Wannabe
