Does anybody know how to richen or lean the carbs on a 72 with SU carbs. If so, how do I know if they are both balanced the same, as far as richness/leaness. I had heard that you could buy a spark plug with a clear insulating glass but was wondering how to do it without one. I have the flow adjusted properly as per my flow meter but, the front carb is so rich that I am fouling plugs. Any help would be very much appreciated.