Carb Question

I recently required a decent looking Edelbrock Perfomer carb. It was ontop of a 2 bbl manifold on a 273 that I bought. The numbers on the flange are 1407. From what I have researched, this is a 750 cfm carb(ridiculous for a 273!!!) Is this the actual cfm for the car based on the part number, or is it a 600 or 650? Thanks.