You will find out that some parts on the B16 intake manifold serve no purpose on a usdm 88-91 civic, and they can be removed. You may notice a few vacuum lines going no where or are open here is a vacuum diagram
A and
B use a t-fitting to make into one line and connect to
F
C connect to
H
D connect to intake buy connecting into the pcv valve line that comes from the top of the valve cover to the intake with a t-fitting and connect to intake.
E connect to
J
I conect to
G
This is what it should look like once it is connected