Update.. I had the tank installed and when the installer transferred the pump/float for the fuel level, they must have banged it pretty good so that when I still had about 30 gallons left, the light was coming on and the gauge was on E. My buddy has a Ford and they were able to tell the computer to calculate based upon the new size (51 gallons vice what ever was in there before) but I've not been able to get anyone on the Chevy side to figure out where that is and how to adjust it. I have since gotten the fuel float replaced and the gauge is pretty accurate now but I would never recommend the place that did my tank install to do anything on my truck or RV again.
