Reply to "Vacuum line diagram"

The blue gizmo in the back of the carburetor needs manifold vacuum. That's a de-choking gizmo, officially called a "choke vacuum control assembly", it was installed to achieve "staged" choking. If you're keeping the Motorcraft carb, then you need to keep that gizmo, I suppose. The guys in Dearborn & Detroit were grappling to deal with emissions regulations, which were tightening on a yearly basis, and were enforced upon them with insufficient warning, and without enough time to respond. It was a very dysfunctional situation.

The other blue gizmo, near the twist cap on the valve cover, that's a decel valve. Its part of the distributor controls. It reduces hydrocarbon emissions when you let your foot off the gas pedal (deceleration). Its most likely non-functional considering its age. My advice is to make it disappear.

FYI: when California instituted vehicle emissions equipment inspections and tail pipe emissions testing in the mid 1970s, I made a lot of money helping people comply (side job).

-G