Ed, Bacon & John --- Thanks so much for the ideas!
I have had this big truck about 10 years, my neighbor (previous owner) purchased it new. I'm getting kinda up in years , and this heavy truck is ... well, getting heavy for me to handle.
I am facing the dilemma: if I loose my storage in the old machine shed, then I have to move it 12 miles home and stick it in the backyard. Backyard big truck repair and maintenance is something that I enjoyed more in my youth. I have been spoiled later in life by keeping a truck in garage. It looks like if shortened to 137" or less wheelbase (about 19feet long bumper to bumper and 81" tall to cab top) it could fit OK in my 2 car garage.
I have driven "shortened" 1948 & 1952 Chevy COE's in workyards years ago. Guys would take a big old AD farmtruck & cut sections from the frame rails and reweld , shorten the driveshaft, and since it was yard truck work, they would not re-connect the rear brakes ; but simply use the fronts and the hand band-brake on the driveshaft (these yard donkey trucks didn't run the roads much, and if so only under 25 mph). Those shortened trucks used as tow-tractors and as a platform for winches and generators were amazing.
So starting the thought & measuring process:
A) Pick a section of the frame rail not tapered, and where where the front mount of the rear leaf spring is already attached (or plan to drill a new leaf spring front mount) Measure inside frame rail for "sleeves".
B)See how much the drive shaft would need to be cut and re-welded (and balanced)
C)Plan removing old grain dump bed (raise bed up , lower on 55 gallon drums, pull truck from under bed?)
C) New rear brake lines.
D) New tail light/ brake light wiring.
(Bacon, I am still moderated and thus unable to post pics)