[61-63]

The advantage of the Offy over the Edelbrock is carburetor spacing. The Offy locates the carbs far apart, only 3/8" closer than do the real super duty intakes, whereas the Edelbrock jams then up very close to one another. You cannot use the '56/'57 Corvette air cleaners that the real SD sets used on the Edelbrock intake because the carburetors are too close together.

You didn't say what year your car is (or I missed it?) but an Offy set on a '61-'63 car looks almost like a real SD set. Here is a picture of an Offy set on a '62 Catalina, with spacers. The carbs are SD clones but generic AFBs look good too.