FWIW, many years ago on my 67 GTO dirt car, I tried the cowl source of air with a 73 style air cleaner with the fuzzy hose connecting the air cleaner to the cowl area. It was the same idea that Jim Hand used on his wagon. It worked well enough that the buttmeter could discern a difference over just under hood warm air.
The problem was that not only did it pull in higher pressure air, it also pulled in a ton of debris such as dirt and small stones that ended up in the air cleaner housing. Looking back, I should have done some further investigation into this modification and solved the problem with a screen, or a layer of cloth to keep the larger stuff out.
Whatever the reason, I never tried it again, but probably should have as the cooler air, with some positive pressure, definitely made the engine run better.
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Brad Yost
1973 T/A (SOLD)
2005 GTO
1984 Grand Prix
100% Pontiacs in my driveway!!! What's in your driveway?
If you don't take some of the RACETRACK home with you, Ya got cheated 
  
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