IMHO the Edelbrock RPM Airgap is the preferred manifold for street, especially in southern locals where summer heat is higher.
The Holley double pumper carb gives good throttle response at the expense of fuel economy. For road racing or circle track the throttle response is of prim concern. For drag racing especially in an automatic transmission car there may be a small advantage just as the light turns green and the throttle is planted in the radiator. Once the fuel flow catches up to the air flow, single or double pumpers are on equal ground.
For street and to work the best with the Airgap manifold, an Edelbrock AVS2 carburetor provides better primary fuel atomization. This will aid driveability, throttle response, fuel economy and emissions.