Help with identifying some parts/carb question
 

First off, I'm curious about whether I've got an aftermarket header installed. The P/O claimed it was and it doesn't look like the ones I've seen on junkyard cars, but I can't find any markings on it.

The pipes are pretty long. It's hard to see it in the pics, but the merge about even with where the prop shaft hooks to the transmission.

Next, I'm wondering what this sensor(?) that sits above the thermostat is. The wires are cut , but the car runs pretty well. Do I need to replace that? What is it even? I can't find any wires that it might've connected to, either.

My biggest concern is my carb, which was stripped by the last owner. I have no idea if he followed the guide or how closely, but my car doesn't like starting in cool weather and I don't like having to manually rev it to 3k for a while after getting it to catch.

So I bought an unmolested carb from a parts car. I'll rebuild it, and remove only the absolute non-essentials. Thing is, it's got a wire, a single male blade connector, coming from the rear choke assembly, which I'm keeping on the carb. It's got nowhere to connect to, either. Any ideas where it goes or what it controls?

Sorry about the long post and thanks in advance.

Yes those are headers

The cut wires at the back of the pump is the water thermo sensor, i know they are important on FCs, i'm not so sure on a FB being its carbureted, someone who knows much more about FBs will chime in

Thanks, now that I know what that sensor is called, I've found a few threads on it. And I'm glad I can save some money on the exhaust system.

Also, after looking at the Haynes wring diagrams a bit more closely, it looks like the wire coming from the choke assembly is for the carburetor heater, so it should function without it, just maybe not as well. I'll probably try to find the connector or run a new wire, though.