Quote Originally Posted by Gusaroo
How about all those engines with dual quads running two smaller filters...? I see them all the time. I would assume that twice the carb is not half the intake flow...

It's pretty close to half the flow of a single carb engine when comparing both at full throttle.
That's why stock jetting works well in a multi-carb setup in the initial stages of tuning.
And sometimes it's right on the money.

Dual quads are generally 8 1/2" - 9" apart on center so that means your air filter would be about the same size with height depending on what you want, but 3" is a pretty common height.

Running the math shows about 91" of filter area for each air filter.
182" total and referring to Tech's required air flow figures you're in Fat City with dual quads.