Holley 500 CFM 2 Barrel #0-4412S on a Slant 6

StrokerScamp said

As thought, the four barrel (AFB) was more responsive but didn't really add any power. While it did have more punch on the bottom end because of the smaller primaries, it was still just as limited on the top end. It was on a 318 in a Duster. A four barrel will always be more volumetrically efficient....but comparing apples to apples the power will be about the same. The power curve is what changes.

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That's interesting, and it would seem to tell us that at full throttle, even with what is effectively, a smalller carb (when rated at the parameters that Holley applies to 2bbs vs. 4 bbls) it still has sufficient flow to make as much power as the rest of the engine can support. The better torque, at lower rpms, exhibited by the 4-barrel carb, is evidence of better fuel atomization and distribution, even though the carb has superior total flow capability.