You got me there Jerry, I can only imagine its mechanical. Do single barrel carbs usually have vacuum controlled valves? I think you would have been the best one to test these carbs out. My carburetor knowledge is very limited. I can only adjust the carb like any other regular guy can with the vacuum gauge. But I cant imagine its too far off its ideal. One can tell by the smell and the feeling of the vehicle if its too lean or too rich.
