No, you want to see what the total MECHANICAL advance is.

The vacuum from the no load scenerio in your garage would probably pull in additional timing.

Doesn't he need to have the vacuum advance connected to check "vacuum advance"?

Have I been doing it wrong all this time?

Edited August 4, 201312 yr by rcb280z

Check the mechanical advance separately (remove vacuum hose) and then check the vacuum advance separately at idle by connecting the vacuum servo to a vacuum pump (Mighty-Vac) or manifold vacuum. Add the 2 together for the total. There are advance curves for each in the factory service manuals. If everything is working properly they will compare favorably to the factory data.