1948 F2 vacuum advance question

[redmodelt]

1948 F2, 226 engine
When I check the function of the vacuum advance, do I just check that it works or should it hold a vacuum? If it should hold a vacuum, how much?
I don't recall seeing this info in the book that came with my vacuum pump/gauge setup.
Thank you
MarkG

I have a rebuilt carb coming. It had been on the shelf for a while so might need a little lube. I will see if this help get rid of the dead spot when taking off from a stop.