67mustang302

It depends a lot on the carb, and also depends a lot on the engine setup. A 347 with modern heads and a modern cam will be a lot more efficient and pull signal better. A modern carb with more sensitive boosters and circuits will operate with less signal.

That said, most people do over carb....they go buy 750cfm basic Holley's with craptastic straight leg boosters. The more sensitive the carb the larger you can go to reduce top end restriction. THAT SAID......you'll generally get a better performing car with a smaller carb than a larger one. There's a point at which the carb ceases to be a restriction(or enough of one to matter in terms of power), beyond that you gain nothing....however more sensitive boosters with smaller venturis means more circuit response.

It also depends on how you use the car....a drag only car that stages on a transbrake at 5,000+ rpm can obviously use a larger carb, since circuit sensitivity below launch rpm is meaningless. A street rpm range car(up to say 7,000rpm) that is driven regularly can't get away with the same setup and retain the kind of response you might want.