you will find a range of 0 to around 20 in/vac. you need to be more specific. vacuum changes under different load and conditions.
thats a good link. but according to it i have bad rings. i suspect that my cam is why its vac is like that.
Maybe we can get a 2 for 1 deal on those rings. Mine must be really bad. Sarcasm aside good link for a stock engine.
A stock 302 ( 8.5:1 compression, Stock cam, heads, intake and car will have 17 - 21 inches of mercury at an idle. A change in any of your components will change that spec.