[Tom Goldman]

I've experimented with and without air pans on many of my own and customers car over the years .
The bottom line is , "your results may vary" ...
If your hood scoop is at least 3 or more inches above the carb vents ,an air pan will nearly always net an improvement ,however some combos do not like total pressurization and need '"vent " holes in the pan . this is due to scoop design ,frontal area ,turbulence and carb calibration, and a million other things that cant be discovered without a wind tunnel !
Carbs that are very close to the scoop usually are somewhat indifferent to air pans ,or at least ones that are tightly sealed.........I've been told this is due to the incoming air having to make a sharper turn at the venturi and creating turbulence.
when I went to the triangle opening scoop on my Vette it completely changed my fuel curve and Air/Fuel ratio. . .....It was necessary to put two 3/4" holes in the pan to reduce the pressure inside the scoop.