Guys guys guys...dyno testing tells all.

Go back to Steve Dulcich's Junkyard Jewel 400hp 318 article, the one where he ported the 302 heads to within an inch of their lives and did some dyno runs.
That ultra heavy mid-70s 360 EGR manifold was only something like 25hp down on the Perf RPM at the top end of the horsepower charts. That intake is really good, just don't drop it on your foot!

Take a long look at it. It is a true highrise design, the ports are 360-sized and have decent curves. It was probably developed with a real eye towards fuel distribution.

It is a spreadbore intake, made to use a Thermoquad. The Street Demon will bolt right on, the SD is made to fit on either squarebore or spreadbore intakes.

About CFM: The Street Demon, the Thermoquad, the AVS/Thunder Series carbs, and Quadrajets all have adjustable air doors which will only let the carburetor be as big as the engine "wants" it to be. You could put a Thermoquad or any of those other carbs on a Slant Six and have them work properly. My Mercedes 173 cubic inch six came stock with a German copy of a Quadrajet that probably flows 700cfm wide open.
Holley vacuum secondary carbs also tailor the carb size to engine demands.

R.