intake question

Unless you have increased the engine’s ability to pump more air, in other words oversized valves, performance camshaft, compression increase, and larger exhaust system including headers or Dutra Duels, a 4V carburetor will be over kill.

Just increasing size of exhaust will be of benefit with both a stock engine equipped with a one barrel, as well as a duel one barrel carburetor set up on a stock engine, as the duel configuration will act as a small two barrel carburetor similar to a super six set-up.