anyone found a good resto guide anywhere?

[gmc1971harwich]

i was pulling my hair out of my head yesterday trying to piece together my under dash venting and messing with my steering column when i came to the conclusion that i reeeeeeally need to find a good assembly manual for my truck that will show bolt and nut sizes and exploded views of everything. has anyone found a good assembly manual anywhere? where can i get one. I have one for my GTO thats perfect it lists everything and anything u could possibly want to know about how things go back together but I cant find one for this truck please help guys!
i know LMC has some pictures about how things go together but they still leave alot of gaps when ur assembling stuff that didnt have nuts and bolts when u got it. lol