I bought one and I didn't really like it. The brass adapters for the two inner carbs were too short, making them a pain to install and remove, and there are no dampeners for the mercury columns. The columns bounce around so much at idle that it's practically impossible to get the proper sync. I bought a set of four vacuum gauges and they are soooo much better. The brass adapters are nice and long and the gauges have adjustable dampeners so you can get a little bouncing, but still read the dials pretty accurately.