In this photo the tank appears to be a tad low. However, that was before other suspension operations. I keep the bottom of the fuel tank no lower than 1-foot above pavement. If more weight, I just add air pressure to the air-shocks. Now, the truck looks right with the higher rear end because I raised the front end with Pro-Comp leaf springs, so the bed is more-or-less level.

As I think I mentioned previously, my mechanical fuel pump pulls fuel all the way from the rear tank with no problem.