4wd conversion questions / suggestions HELP!

[Griffin]

i have a 67 LWB GMC 2wd that i want to convert to a 4wd. I have a 76 chevy 1/2 ton donor truck with a dana 44, 12 bolt, sm465, and np205. I have the whole rollong chassis of the 4wd. I've considered doing a full frame swap but i know that will be a huge pain b/c of building new cab and bed mounts. But, i have no idea if the 76 steerng box will bolt to my 67 frame, will the 76 front spring hanger work (i know anything will work with a welder and enough patience), do the axle pad line up the same width as on 67-72 trucks or do i need to weld up new mounts, etc...Will i have to change the negine crossmember? Basically, i'm a pretty good fabricator but i've never done much 4wd work...i.e. setting the caster, pinion angle, etc. Anybody got any advice/experience with this swap?