DING, DING, DING, DING!!! We have a winner folks. Bill, your idea has sound properties but in practice it's not very workable. You could put a small cowl scoop on it and just leave it open, not sealed to the carb or anything and it would let hot air out when you are stationary. And that is not something to sneeze at because you can cool down a hot engine compartment much quicker when you allow the hot air to rise and escape. I noticed a big difference in my Duster when I just cut the lip off the fiberglass hood that extends all the way around the periphal edges.
