I want to check the vacuum pressure levels on my car but not sure where to hook this up to. And what reading should i get?

I always used the vac port on the passenger side of the upper plenum that feeds the fuel pressure regulator.

With a stock cam, somewhere in the 15-17" Hg range at idle is usually good.

You're looking more for fluctuation...at idle, the needle should be rock steady w/ a stock cam. Even my lumpy HOT cam pulled 12" steady at 800rpm idle. If the vacuum is bouncing around, you have problems.

mine was reading around 15. The idle would go up once in a while for some reason and it might reach 18 at those times. The reason i was checking is cause of this searching idle problem. But when the idle was even the meter read about 15. So does this eliminate any vacuum leak concerns?