71 Dodge Dart Swinger in England

I check my timing idling full warmed up with vac disconnected and plugged, once its connected, the mark runs off the scale. It sounds about right 8-10 BTDC w line disconnected. Running it open headers can also make it seem to feel like a stumble. If your car is factory A/C theres a vac line that goes from the back of the intake manifold to inside the car. It operates the vacuum solenoids for the blend doors etc. If not just plug it at the intake manifold.

The carbs usually come with more vacuum ports than needed since they are universal carburetors, just plug the unneeded ones with rubber vacuum caps. The routing of the yellow is fine, but the distributor body should be facing where the vacuum advance points towards the right side of the car, and the vacuum line should route along the right side of the intake manifold and stay away from the linkages.