Using vacuum gauge to tune engine?

Than you everyone for all the advice and mopardude318 for the video. I do have another question for everyone. Everyone talks about ported and manifold vacuum. If my 383 has an electronic distributor with no vacuum advance how do you set the advanced timing? Also if my manifold doesn’t have a manifold port how can I take vacuum off of the manifold? I adjusted the timing and fuel/air mixture by using the rear port off of the demon carburetor on the passengers side. I read that is what you use. See photo.

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