In the beginning you used the words "disc brakes". Have you converted your car to disc brakes? If so are you certain the system is workable with our cars?
Mack, I am going to insert a few pictures that may help.
First some basics. Off the intake manifold connector you should have a fitting with 2 nipples (maybe 3 if you have vacuum power door locks & trunk). One of the vacuum lines goes to the throttle check valve at the firewall to control throttle deceleration, and the other goes into the main forward lamp harness wiring block to feed the Neutral Safety Switch and the AC/Heat System. Throughout the pictures below I have highlighted these 2 vacuum lines in yellow.
Second, at the round engine cranking harness connector, you should have one blue striped hose on AC equipped cars that feeds the Fast Idle (Speed-Up) Vacuum Power Unit. I have highlighted it in blue.
3 obvious alterations to your car, is a 2nd line at the round engine cranking grommet; the missing cabin feed line to the main wiring block;, and an altered back of intake fitting that I am not sure where it goes after the short hose then a worm gear clamp. For the 2nd line and to see what is on the back of the main wiring harness block and what happened to the main vacuum feed line, you will have to get under the dash and see where it goes. Anything beyond that on my part is pure guesswork.
Here are some pictures that may help:
This is a stock setup showing the intake fitting going too the throttle check valve and the cabin vacuum feed at the forward lamp harness connector (yellow), and the fast idle vacuum unit (blue).
Here is another view noting that the Idle Speed-Up Feed is cut and disconnected:
Here is the same picture with the color highlights (yellow for intake to cabin feed at forward lamp harness connector and Throttle Check Valve; and blue to Idle Speed-Up)
Here is a picture showing the relationship of the actual pictures to the shop manual illustrations which does not provide details of the intake fitting connections:
These illustrations were copied to our Vacuum Schematics and Pictures Help Page. They are not the definitive pictures I would like to have on file but hopefully will help someone.