[Automotive Stud]

What intake manifold are you running? If it has the carburetors set back for generator clearance you'll never be able to sync them with the air flow meter, the rear carburetor will have to be so far open to compensate for being so far back that the idle will be racing.

If you have a manifold where they are spaced evenly apart and you are using direct non progressive linkage then they should both have idle speed screws and they should be tuned so it idles nice and pulls the same amount of air through each carburetor.