both of my cars are street driven. one runs at very reasonable temps during the summer and the other runs hotter than i like. both use carter 6903 pumps and return lines. my '69 rt uses the factory style and my 65 coronet uses something i made. i do use heat insulator gaskets for both cars and neither has ever had a hint of vapor lock. the alcohol in pump gas is a real pump gas problem with no solutions. i think the only real solution is adequate fuel pressure and a way to push the vapors out of the fuel line no matter mechanical or electric pump. basically, don't dead head the fuel line.