Doug, did you get the specs for the distributor when it was rebuilt, and were you connected to ported or manifold vacuum source? Adjustable or stock vacuum advance canister?

The Pertronix is simply an ignition trigger. It replaces the points. If you've wired it according to the installation instructions and have the proper voltage to the Pertronix ignition (which MAY be different than the voltage to the coil, depending on the coil) then it should work just like points but with a non-adjustable dwell and no high speed bounce. It does not affect the vacuum advance, but it is often necessary that if you modify your factory distributor curve that you must also install and adjust an adjustable vacuum advance canister. And, as noted, some modified distributors use no vacuum advance at all.

Leaving the vacuum advance disconnected may prevent your engine from running optimally under light loads.