Pumping the gas pedal - alot

I recently acquired a 1967 Dodge Dart GT convertible with a 273 V8 with 2bbl carb. If I have not started it for awhile, I have to pump the gas pedal about 8 to 12 times to get it to start. What could be the issue? Would it be the fuel pump or the carburetor? The 2 bbl carburetor is a Carter #2310, indicating it is off a 1952-1954 DeSoto with a 277 Hemi. Is the correct, and if so should I replace it? Thanks.
I read in an article on how to start the old cars as I forgot myself and would pump the gas quickly and often. It stated to pump two times, Slowly. I tried it and it worked great, and not only a quicker start up, but the car runs smoother on the initial cold idle too.