Chevron,
I will very likely be doing a similar thing to my 70 C10. I’m going to cut the frame down into a short box. Like you, it’s not for sale. Ever. So no worries there.youve already got a short frame, so you’re set there. The frame modification does not worry me much but...
I will not be attempting to modify the box sides. The amount of work for a novice metal worker and skill needed to make it right is very intimidating. I will not be undertaking this task. I will be sourcing shortbox sides from a vendor. The time, skill, frustration, and likeihood of ruining a perfectly fine long box is simply to high for this cat. I’m buying. And this is coming from a guy who has built 2 AD boxes.