Greg---If anyone has a doubt as to whether they have a vacuum retard or
vacuum advance, here's a simple test to confirm...
Remove the distributor cap. Pull off the vacuum line at the vacuum
pot(s). Apply vacuum to the port. Vacuum retard will pull the points
plate counterclockwise, which of course will retard the point opening
event. Looking down on the distributor from the driver's side fender,
this will be the pot on the right side of the distributor.
The opposite will be true for a vacuum advance pot. This should always
be on the left side of the distributor, and applied vacuum will pull the
points plate clockwise, advancing the points opening.
If you have both pots, they will do their thing depending on which one
has the stronger vacuum signal.
Dick Taylor
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