My stock moved air about 60mph (IIRC) at about 2000 rpm but at speed you have air moving on both sides.
I suspect the air under the hood will be moving slower than the air above the hood and create a low pressure where the slits are but where the cowel is the air gets compressed trying to turn and creates a high pressure.
It will be very I tresting.
:popcorn::thumbsup:
Makes me want to get out the yarn and masking tape!