Vacuum system question

[Doug Yoder]

Re de-bugging my dead '87 5kS wagon...

There is a 4-way connector on top of the valve cover/cam cover... it
connects to the ISV, the cam cover, and has hoses making a couple other
connections.  I believe this is part of the "crankcase ventilation".
Question: is this 4-way connector supposed to have a one-way valve inside
of it?  If so, where can I get a new one and how much should I expect to
pay?

Thanks,
-Doug