Being off by one tooth will certainly make it hard to set timing,,moving the wires in the dist cap by one position would take care of the problem,,at least for your own use.
Intake manifold Vaccume leaks are a common thing to have,,,most of the time it's from installing an aftermarket intake manifold which is not planed at the right angles.
Other than that,,,it's a gasket not lined up properly,,or sufaces not prepped properly before installation of new gaskets.
Originally posted by 58'chevy
A couple questions for ya...
If the distriburer is of by 1 tooth(too far ahead) how much would that affect the engine?

How common are vaccume leaks from the intake to the heads?
Thanks!
Mike