If you are talking about a Suburban/Blazer gas tank between the frame rails at the back, I have seen that done. I think you have to move that rear brace. Now as for putting that bed on one of these trucks, well I dont' care for the idea, but I haven't seen one done. I've seen them on a 55-57 didn't like that, seen them several times on 67-72s didn't like that either. The 77-87 stepside bed looks good, what's wrong with it? But If you want to be different go for it. Good luck.