Had a question about the vacuum line hooked up to #17:

Should I be able to hear this hissing at idle? The line isn't leaking itself but I can hear it hissing inside the pcv tube where it hooks up. If I pinch it, the hissing obviously stops and manifold vacuum rises a very small amount.

This car was butchered so I'm trying to get it all back together but I'm wondering if I'm missing something.

There are no cuts or tears in the line or bad connections. I've checked them all with a mity vac. A line from the manifold and evap come to a tee, this hose connects on the tee and goes to the pcv hose.