Definitely agree that return less is the best system to use with a fuel cooler. However, using the ac to cool the fuel is not a good idea. You would probably use as much horsepower running the ac compressor as you would gain with the cooler fuel. Then how would the atomization be at the injector with fuel between 30-40°F? I will admit to not knowing much on fuel atomization.
If you really want cooler fuel all the time just put a small fuel cooler in front of the radiator. Is it safe, not really but I have seen it done and it helps. Especially on SBC vehicles with the block mounted pumps.
