72 Duster Resurrection

Ok, while the engine has been gently idling for a minute, the instruments settle to this state

Your temp gauge is about to cook to death. Your fuel gauge may very well already have been cooked to death. If the instrument cluster voltage regulator (plugged onto the back of the instrument cluster -- not the same as the voltage regulator in the engine bay) has failed with its points stuck closed, the fuel and temp gauges will peg and then cook to death, not necessarily at the same time. If you need a new ICVR, the best one is here. However, that's not the only possible cause of this what you're showing us. The ICVR could be fine and you could have a hot-pegged temp gauge reading because the wire from the sender to the gauge is shorted to ground somewhere along its length, or the sender (screwed in at the top-front of the engine) could be faulty; meanwhile your empty fuel gauge reading could be a faulty fuel gauge sender, or the sender could be fine but its float could be sunk, or its float could be fine but it's lost its ground.

Float: Ford P/N COAZ-9202-B
Strainer "sock": GM P/N 5651 705 (buy this in any event; you will want to replace it if you pull the sender)
Gasket: Chrysler P/N 6031 475
Sender grounding clip: Chrysler P/N 2258 862.

If you go removing the sender from the tank, you probably don't have the special lock ring wrench, so use a non-sparking drift (NOT made of steel or iron!) to knock the lock ring loose and then re-tighten it. Otherwise it could be the last advice you ever ignore.

Voltage staying at a negative current draw position when the engine is not running and jumps to what the pic shows when the engine is idling.

Fine/normal.

Yeah I love rock auto

Don't love it too hard. Their catalogue is not flawless (contains errors) and you have to really be on your toes to get good quality parts for older cars like ours. Way too easy to get poor-quality junk these days. Consider better-quality parts from the likes of Old Car Parts Northwest and/or other sources listed here.]here[/url].

However, when the gas feed line is attached to the carb, the engine will not start. So I need to break the carb down, clean, inspect, and possibly rebuild. No surprise there.

See post № 11.

But I am going nuts trying to find the right rebuild kit.

You haven't found the carb list number yet. None of your photos shows the correct view, which is of the front-facing "wall" above the float bowl, not far from the curved bowl vent nipple. It's worth looking again; all 1920 kits are not alike.

Moreover, don't be too surprised or disappointed if this carb, which has already been abusively "remanufactured" at least once, does not respond fully or well to your rebuild efforts. Still worth doing it in case you get a good result, and for the learning experience, but.

I know that third pic with the numbers 0509 and 4164 are supposed to be the ones I need

Nope.