I know this post is about using a carb mate tool, but I'll throw this into the mix incase some one reading these messages is wondering what to buy to sync their carbs. I've been using a single vacuum gauge with a T in the line coming into the vacuum gauge. Each line going away from the T has a valve in it. Those lines then go to the ports on the intake manifolds. With it all hooked up, open one valve and you see the vacuum there. Close that valve and open the other and see if both readings are the same. Adjust the linkage so they are reading the same. Even if the vacuum gauge isn't accurate, you will still be able to compare one side to the other, and that's what you are really trying to do. JImChuk