Not too much science needed there. We drive cruisers that have full exhaust tailpipes, where most car experts mount the pump is pretty close to the exhaust, warmer than in the tank. We cruise and park on asphalt parking lots for what they call hot summer nights, warmer than in the tank. Inside the tank is a pretty cool place, more so if your tank is undercoated as so many were. My though was only a reliable way for a fuel delivery system to keep positive pressure to the carb after heat soak. Like Bill M., I want my engine to restart within that hour after shutting it off. A couple of hours after some burgers & fries, lots of trash talk my engine will always start.