Some of them are capped some are not. That line your talking about isn't long enough to reach that. It may have been cut.
This is my connecting end like the one you pictured...The black vac line coming from the bottom is connected to nothing and is not capped or screwed off as well.
Actually there should be 2 small vacuum line coming out from under the back of your intake, 1 Red vacuum line and 1 Black Vacuum line.
The short red vacuum line should go to your stock fuel pressure regulator and the black line should have gone to the rubber block with the 5 ports that we are both showing.
If those ports in the rubber block are not sealed you'll have a vacuum leak there for sure.
sorry to revive this thread. better than startin a new one about the same thing. anyone have a picture of that 5 port vacuum thing hooked up properly and what goes where? thanks.