This is what the "donor" parts looked like when partly removed from the 58 Suburban body. The roof unbolts along the sides, and I cut the ends loose. The floor also unbolts at the sides, again I had to cut the ends free.
This is the work on the frame. I cut off the original frame just behind the cab, and added a (longer) rear frame section. The wheelbase increased 24 inches over a normal short bed frame. The cut is angled, and there are fish plates on top of both flanges, as well as on the outside of the frame. It's held up since 1994. I also lengthened the fuel and brake lines, and the driveshaft, exhaust, and parking brake cables..as well as the rear light wiring.
The cab with the rear panel cut off.
This is a test fitting of the new side panel. Note the horizontal slit, about level with the gas filler hole, where the Suburban has some curvature that I needed to remove by adding a pie shaped piece. The window frame is also shortened from the stock Suburban size
Now the floor is added. I cut two feet of Suburban floor, to fit the gap in the truck's floor. The floor is attached to the sides with bolts that go upwards, and at the front and back with carraige bolts. My helpers are testing the strength.
Now the back is attached to the sides.
This is the roof area. I cut off part of the edge of the Suburban roof, and bolted it to the new quarter panel.
Now it's all welded up, and ready to finish. Here you can see the section of Suburban roof that fills the hole. It did not go in quite right, so there are some bulges in the roof. An English Wheel would be nice, to make a compound curved roof panel.
This is the bottom, looking forward on the drivers side. You can see the fish plates on the frame, and the Suburban body mount and cross sill.
This is a look inside. It's not finished yet, but that let's you see some of how I built it. The front seat is 58 Suburban, the rear seat is old school bus. You can see the beige colored part of the side (quarter panel) which is from the Suburban, the original pickup interior is gray. The part below the window was filled in using the top part of one of the other Suburban window openings...as the Suburban comes with sliding quarter windows. The quarter glass is now stationary.