To advance timing, just turn the distributor counter-clockwise a tad and drive.
Repeat this until you hear a slight ping at wide open throttle, going up an incline.
Then retard the last advance you made.
Then, if you like, you can use a timing light to see where the marks are and write or draw a note for the future.
Any popping sounds at deceleration should disappear when timing is advanced far enough.
The ping sound let's you know how far you can advance without getting pre-ignition.
Your vacuum reading is good.
Checking the gauge while driving can tell you a lot about the engine. It will not show your carburetor's fuel mix.
I would check the number on the main jet and compare it with the manual.
Also check for vacuum or exhaust leaks.
