[MrMagoo]

I agree that an electric fuel pump is better as far as heat transfer is concerned, but I switched to a mechanical for several reasons. I hate the whine. At a stop, its nice to hear just engine sounds. Electric pumps don't like being put away for 6 months in the winter (as we do here in Connecticut) amid frequent changes in humdity and temperature. The mechanical is nice in that if the engine fails in an emergency, you don't need to remember to flip the cutoff switch or the ignition off. You don't need a regulator. Less strain on the battery in trafffic. They are very sensitive to voltage fluctuations. One less thing to worry about. And finally, the last reason, an appeal to authority! The gruff and lovable Joe Lapine of Danbury Competition Engines hates electric fuel pumps on street cars.

On the whole, unless I was racing or running fuel injection, I prefer to stick with the mechanical, and do everything else to eliminate heat transfer.

If your sole goal is eliminating heat in the fuel, a system with an electric pump and a return line like you would use in fuel injection is probably ideal.

I don't know about reversing the fuel lines and feeding from the rear. It's an interesting idea and you've probably found that it works, but the conventional wisdom has you looping your fuel line in the front to the carb, with acceleration pushing fuel towards the carb instead of away from it. This may be a case of engineering trade offs, and in a hot place, it may be that the benefits of secondary first feeding outweigh the negatives.