Since I needed to pull the bed on my 1970 C20 to do cab corners, I decided to make it a short bed too. My approach is different than the conversions I see most doing on this site. As a metal shaper, we are taught to plan out our cuts and splices to ease fabrication, save time, and avoid frustration later on. So I came up with a better idea to make cuts and seams easier to do and keep the original paint, well most of it. Here is my plan:
Before:
First remove the bed. I just cut all 8 bolts and unplugged the rear harness.
Remove 8" from rear of frame rails and move the slot on top forward too.
Then remove the front most bed mounting bracket.
Then remove the front rivet of the second bracket and swing out of way. Then mark the cut. I went from the front rivet hole of the front bracket to the front rivet hole of the second brackets.
Then I unbolted the trailing arms from the crossmember, removed all rivets from crossmember and slid it forward 12". I welded in place. Then I cut the frame rails.
To be continued...