This is from the side bar on that same webpage. Read it, and you will see how they contradict themselves.
Quote:
Tuning Vacuum Advance
The last step, after the total advance curve is set, is to dial in the vacuum advance if you have one. There should be a vacuum line connected from the carb, or the manifold, to the vacuum canister. There are two types of vacuum sources that you should be aware of. One type is known as "full" vacuum or "manifold" vacuum. This is a direct connection to the manifold, and if the hose is connected to this port you will get vacuum in the line at idle. The other port is a "timed" port, which only yields a vacuum above a certain rpm. At idle the line will have no vacuum. Most carburetors have both ports. On Holley's the timed is above the throttle blades, and the "full" is below, near the base. On Carter/Edelbrock carbs, the timed port is on the passenger side and the full is on the driver's side. The easiest way to confirm what port you have is to hook up a vacuum a gauge and check for vacuum at idle. The preferred vacuum source is the timed source. This way there is no effect on the initial timing setting.
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