Holley 4160 - fuel/vacuum port identification??

[96RinkerCaptiva212]

Hey guys - I'm upgrading from my older 880 5.7 to a Vortec 5.7 with hi rise intake and 4 barrel Holley. I'm pretty sure I've identified this carb as a 4160. Rapido sold it to me when I bought the long block. I have the fuel inlet hooked up on the opposite side (not shown here) but my question is, what is this smaller brass port? It has a screen on it so it makes me feel like it's a fuel port. I originally thought it was a vacuum port. Trying to look around the net for some pics or diagram but I don't see anything calling out this specific port.

2nd question - This choke thermostat has a positive and negative on it. My old 2 barrel carb only had the positive hookup. Out of that wiring harness for the choke/throttle, there are actually 2 small similar grounds. I'm not sure what each ground is for. Can I just hook up one of the grounds to the negative terminal on the choke thermostat and the other on the throttle bracket? I'm just concerned about proper ground.

 

[kenny nunez]

The port you are asking about is where a metal tube would go to the exhaust manifold if the choke was not electrically operated.
Just mount the ring terminal to one of the screws on the choke cover.

 

[96RinkerCaptiva212]

The port you are asking about is where a metal tube would go to the exhaust manifold if the choke was not electrically operated.
Just mount the ring terminal to one of the screws on the choke cover.

Are you saying leave it open then since my choke is electrically operated? I found this diagram finally which shows it as "Fresh Air Intake", so that confuses me as to why it would go to the exhaust?

 

[kenny nunez]

It is a way to just draw hot air from a cavity that is sealed from exhaust gas and picks up heat. If you look at a car from the 60s you will see how it was used then.
A Ford would be a good subject to look at.