[Daves55Sedan]

Tell ya what. If your intake manifold has the two holes in between the venturis that mate with the two little holes in your old gasket, but the new gasket (which does fit the new carb), but does not have the two little holes, I suggest getting a hollow punch set and duplicate the correct size holes to match the intake manifold.
You can accurately locate the holes in the gasket by setting the gasket on the intake manifold and press a worn (rounded) oversize center punch over the gasket and move it around till it "finds" the hole and press down firmly. Take the gasket off and set it on a clean flat surface upside down so you can see the impression your center punch made real well. Now punch the gasket out with a properly sized hole-punch.
I'm not real familiar with the '57 and later carbs, but in the older style bug-sprayer carbs (Ford EBU, Holley 2100, ECG, etc) there is one hole and passageway at bottom of carb valve base for vacuum to operate the power valve. That could be the cause of your hesitation upon accelleration. There's no vacuum if the gasket blocks it off.