at http://www.network54.com/Forum/88781/ is set the carb up to the "carbs" specs, not the car ie a C5AF A is for a 65 galaxy and should be set up for the galaxy even if its used on a tbird. Hope that makes sense.
They have air bleeds all over the cluster that calibrate the boosters. Any dirt can shut off one side of the the carb. Also, When you pull the cluster, keep track of the weight, spring, and check ball, also don't over tighten the booster they warp really easily. If there is a baffle under the screw, get it even as it can disrupt the flow and cause one side to be out of balance.