vacuum advance, you can watch it move when the engine is revved. And you can check the module by gently sucking or blowing in it. Don't do either very hard, you will crack the diaphragm.
Dwell should be about 32, I usually set with a feeler gauge then check with the meter. V8s were easier, they had a window in the cap to set the dwell. Usually takes a couple of times to get reasonably close.
Do you have a vacuum gauge? It is a big help in tuning these non-computer engines. If your vacuum is low overall, check for leaks, either hoses or intake manifold.
