I'll put my two cents in!! It depends what type of electric pump you have. Some have a hard time with suction and like to be "gravity fed" meaning they should either be mounted lower than the level of the gas in the tank or, even better, as closse to the tank as possible. Some of these type of pumps actually utilize a second pump. Like some ford vans have 2 pumps. Rear frame rails are a common location if there is room.