It's a '89 GMC 7000
I'll have to research that a little.
Most likely firewall mods, yes. No way around it I don't think. However, I think the easiest is to put the engine and tranny in the frame where it wants to go and then just customize the hood. draw lines on it, cut it, add fiberglass. My father does own a body shop don-cha-noe! It will take three pieces. The fenders would have to move back, as well as the mating edges to the cowl. Honestly....that might look pretty sweet. I can put the mounts from the flywheel housing right in the holes and simply move the two cross members on the front of the frame up. They are simply bolted in and the frame rails are straight up there. Just move up, re-drill, put bolts back in. It would just become a matter of making the dayum hood fit and not look retarded.
Fourth edit: I like the redo the hood idea more and more. Actually...I love that idea. It will dang sure be easier than a dog house that looks butchered to schidt.