Series air intake/carb elbow connections

[tolonian]

Hi,
I have a series IIA/3? air intake/carb elbow that has the emissions connections for valve cover breather and charcoal cannister but there I another small connection at the bend where the elbow connects to the carb, anyone know what its for?

[LaneRover]

It is the 'intake' or vacuum port for the PCV or in this case the 'breather' on top of the engine or from the 'crankcase ventilation port' on the oil fill tube.

Your truck may or may not have a different vacuum port it uses.

[Les Parker]

20150217105024882.pdf

Pics of the vacuum system. The centre hose of pic # 2 goes to the elbow on the air cleaner duct.

Hope this helps.