Once the engine was repaired I was ready to start tackling the bed of the truck. Unfortunately at some point someone decided to weld the bed of the truck to the frame. It was a total mess - in place of the original wood bed, a 1/4'' diamond plate was welded all around. Though it served as a solid floor, it isn't what I wanted, so it had to go.
With my trusty 4'' grinder I set out - it took about a month to find and grind through all of the welds. Working alone, I also had to cut the diamond plate into three different pieces - it had to weigh close to 300 lbs!
Once the diamond plate was off the rest of the bed disassembly went quickly. Installing the new 'under-box' tank was easy and didn't require moving the crossmember. I drilled 6 holes and it bolted in.