390 cfm

RustyRatRod said
That's how I have mine mounted. Even if it made a difference, how MUCH can it be?

Look at it this way. If it DID make a difference, every Super Six made would have a sideways mounted carburetor! I wouldn't sweat it.

Engines on dynos don't move around either, fuel sloshing around with the carb sideways can introduce it's own set of issues, for no significant gains.