X2 on what Perfacar said. My 408 is a single carb that makes about 440 hp and a stock pump ran out of fuel half way through 2nd gear. Changing a fuel pump is easy though so if you want to try it go for it. Then if it doesn't work you can swap it out.
BTW: I hope your not still running the stock a-body 5/16" fuel line and pickup for 2 600 carbs. I can't imagine they'll do the job