Before you pull the carb off hookup a tach and slowly bring the rpm up to see what rpm the primary boosters start to flow. Don't be surprised if one side starts flowing sooner than the other if you are using a dual plane intake. Also bring the rpm to 2k and see if the motor runs cleanly, this would be the upper side of the idle transition circuit, you are looking for a lean misfire. All this is done in nuetral. When you check the emulsion well holes in the metering block you may find one or more plugged with crap.