Edelbrock......and my vacuum gauge both say the opposite of what your so called gurus say. The driver's side port is manifold vacuum and the passenger's side is ported, just as in the diagram above. I have an Edelbrock on my F250 and it has the ported vacuum port exactly as in the diagram above.
That said, the guru that told you not to use the vacuum advance is an idiot, just to clear that up now.
The purpose of the vacuum advance is to pull the timing up on part throttle, when the vacuum is high. This helps clean up unburned fuel that would otherwise be wasted out the exhaust on part throttle.
It also aids part throttle response. The last benefit, which is a biggie, is that it increases fuel mileage and by a good bit. Usually 2-5 MPG if tuned correctly. So anyone who says not to run vacuum advance on the street doesn't know a farfegnoogen thing about how it works or what it does.
Just because guys disconnected it forty years ago and thought it was cool doesn't mean it's a good thing to do.
The vacuum advance will even work with large camshafts, as at part throttle, vacuum is greatest in any engine. The bottom line is, if you drive your car on the street AT ALL, you will benefit from vacuum advance, PERIOD. End of story.