Vacuum lines, Brake Booster intake connection

[88YJ6]

Hey so just re ran all most of my vaccuum lines in my 88yj 4.2L with the 2 BBL Carter...i know a pos....anyways when the brake booster connects to the intake manifold there is another vacuum port but I dont have any idea where it is supposed to run. According to the diagram I have in my Chilton manual it doesnt even show the brake booster connected to the intake, so I have no idea since the last guy who ran the lines ran them incorrectly and I didnt take photos of how they were run before.