i have a 5" cowl hood on the 'cuda and LOVE it. will never change it either. my old 6 pack hood tried to fly off the car every pass, got tired of that real quick.
and like mentioned before, none of the heads up series allow forward facing scoops, whether it's factory or not.

big pro stock scoops, snorkles, even the hemi scoops look like crap in my opinion. if it aint pro mod or pro stock, don't put a big stupid looking scoop on the hood. just my opinion.

nothing like outrunning a big tired, lexan windowed, pro stock scooped car w/ my street car

i switched from a 6 pack scoop that was sealed to the carb to the cowl hood (carb not sealed) and saw NO change in performance. did that when the car was running mid 10s.

i can barely slide my hand b/t the back of my scoop and the windshield. from what i've seen, this is how they have to fit to draw any air.
every single time i've seen an A body hood test done, the cowl hood was WAY too far off the windshield to do any good.
not calling him out or anything, but Knowsnothing's test...he lost performance from his Duster b/c his cowl hood was too far away from his windshield to work properly.
i see people mention they lost power w/ a cowl hood and just about every time it's because of that issue. CHIP