There's no secret. A single tap gives you one vacuum signal. Two taps (at the base of each carb) gives you two vacuum signals, each slightly different. Then you need to decide which one the distributor needs to use.
Kevin 1951 Chevy 3100 work truck Follow this saga in Project Journal Photos 1929 Ford pickup restored from the ground up. | 1929 Ford Special Coupe (First car) Busting rust since the mid-60's If you're smart enough to take it apart, you darn well better be smart enough to put it back together.
