The vacuum is an input to the controller and of course changes the timing. Moving the distributor should not. Other than changing reference resistors where aplicable (or altering the vacuum signal) there is no way to positively afffect timing. I say positively because (for those who think they have) the only thing that moving the distributer does is creat a booster gap by not having the spark occur while pointing at the terminal it is supposed to leave on. This condition will eventually lead to the destruction of a relatively indestructable cap and rotor. It could I suppose look like a timing change as the booster gap could alter idle performance and manifold vacuum thus changing timing. Who knows the controllers on these things just sit there, they never go bad and most of us never even diagnose their strategies. They might have a mapped strategy to alter timing as the secondary kv changes versus manifold vacuum.

The timing IS NOT adjustable.

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Steve Brotherton
Continental Imports
Gainesville FL
Bosch Master, ASE Master, L1
33 years MB technician