A 90 deg fitting goes to it then leads a vac pipe across the top of the firewall to a 4-way vac connector in the vicinity of the brake booster. The three-way output then goes to the "ECONOMY" gauge, driver's door lock and some mystery location I have yet to find.
That vac spigot is a common source of vac leaks since it is difficult to see and access with the engine installed. It is often overlooked when troubleshooting vac leaks.
If that is the drivers side (LHD) head it is the oil tube that goes to the oil pressure gauge. It has been broken and spliced with the tube and hose clamps. There should be a penetration in the fire wall just above this head.
Broke mine a month ago replacing the heater hose.....$90.00 24" long piece of plastic tube. Comes pre-assembled with fittings on both ends and firewall grommet. I wouldnt run it with the splice.
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