From Hughes engines.
"Edelbrock Victor 440 Single Plane
Stock average 314 CFM
Big block Edelbrock RPM
Stock average 285 CFM
Holley Street Dominator B/B
Stock average 282.3 CFM
This manifold is designed for a spread bore carburetor, like the M-1. Like the M-1, your money would be better spent on the Edelbrock Victor intake."