Missing air cleaner parts and connections

That's an interesting approach...:)

The correct arrangement is this:

First, as mentioned, you are missing the carburetor pre-heat valve on the air cleaner. Seeing that you are from the south same as me, it probably got removed by a previous owner because they decided it was a "restriction" to that 100-hp Slant six.

You'll need to fix or replace the air cleaner first. That may not be the original anyway because I think only the later version had round inlets.

Then, flip the air cleaner base over so you see the bottom. There's two vacuum nipples there side by side. That's the thermostatic temperature switch that permits or cuts off vacuum to that flapper depending on the temp in the air cleaner. Cold, vacuum flows and shuts the door, Hot, the vacuum stops and the door stays open.

Anyway, one line runs from that valve to the flapper door in the snorkel. The other runs to a vacuum source at the carb.

In this case, I see that someone has again looped the two connections on the Holley 1920 cause they didn't know what to hook to them. When you look at the left(driver side) of the carb where that loop is, the FRONT port, meaning toward the radiator is where you connect another vacuum line that you install from that thermo valve on the BOTTOM of the air cleaner. Then you are finished with that.

Regarding the other port in that "loop"..the rear one: that is supposed to be connected to the choke pull-off that is about 3 inches above it.

Onto that apparatus mounted on the side of the air cleaner:

That's the OSAC valve. In everyday terms, it's a delay valve for the spark advance signal to the distributor. One side is labeled CARB and connects to the carb, the other is marked DIST and connects to the advance on the distributor.

I normally try to keep things original but that was a poor idea to try to reduce emissions. You can get a slant air cleaner which does not have that thing in there. In fact, through 1973 the OSAC was mounted on the far right of the firewall.

Hope this answers your questions.

To the poster above:

You are probably thinking of the thermostatic vacuum switch that was mounted in the radiator and controlled the vacuum flow to the EGR valve depending on coolant temp. Easy to confuse:D. Later on that switch migrated to the cylinder head.