Is there any scientific advantage to one or the other? I've noticed on our dump trucks they all have the fuel feed line at the bottom of the tank, odd because of the off road application. Yet all of the tractors have siphon feeds off the top of the tanks, these trucks rarely leave the blacktop. Just curious why there would be a difference.
Just theorizing her but I don't think an off-road application would fare well with stand pipes. I would think they would crack and suck air constantly. A bottom feed would not be susceptible to vibrations and stresses off road vehicles are subjected to.
i don't know about scientific. but the advantage of top draw, which manufactures started going to in the 80's, is you don't have to worry about getting a fuel line jerked off by an alligator. some truck owners, that started having tank equalization problems, would shut off the return line to one tank and run a crossover line between the 2 tanks so they would equalize. which may be what you are seeing. or it just may be the old style bottom draw-top return.