No issues with pump mounting height AFAIK, think mine sits at roughly the midpoint of the tank. Theoretically you could even put it underhood, but it's best to put it as close to the tank and as low as practical. That helps ensure the tank-to-pump line remains primed with fuel most of the time and, even if it drains dry somehow, minimizes how much time the pump would try to pull an air vacuum until fuel reaches it. BTW, in case you wanted to try mounting it vertically somewhere, I'd put it intake end down, output end up.