but found on P5b.
On my NADA the take off has 3 vacuum points.
1 air con/ heater unit.
2 air cleaner with hot/cold intake.
3 throttle switch to control distributor advance retard for emission purposes.
thats the vacuum takeoff port, can have up to three outlets but yours looks like it's a single, they are rather rare on a P6B but found on P5b. I forget what it's for...but i think it connects to the Automatic Enrichment Device (AED - choke) which few P6Bs had. That car of yours appears to be of mixed provinence. What is the bracket in the forground for?