carb size

i have a question about carb size i have a 4000 lb tbird with a 429 thunderjet 360/480 engine the previous owner put a 750 duel feed double pumper holley on it an a performer 460 intake an its down on power an low end torque is this not the right carb for a heavy automatic if so what would be a good choice my other car like this one was stock an would run circles around this one thanks.

Probably needs to be properly tuned.