One thing that I see that may need attention. On your outside carb linkage, you have stops placed in order to actuate the carbs at your predermined point. If you haven't already, put a stop on the other side of the arm as well to aid in returning the outside carbs to fully closed at idle. I found that mine would linger open sometimes and not allow the return to idle. Just my 2 for what it's worth-Keep up the great work!