Hi. You can PM me through this board for starters.
Lets work backwards through your findings.
It really does not matter which terminal on the gauge is connected to the stabilizer "I" terminal. The later gauges (like you should have) are very simple devices. A resistance wire is wrapped around a bimetallic strip connected to the gauge's needle. Current flowing through the resistance wire in the gauge causes it to heat up which in turn heats and deflects the bimetallic strip... moving the needle. The sending unit is basically throttling the amount of current flowing. The current can flow either direction to heat the wire... so it doesn't matter which gauge terminal goes to the "I" terminal or to the sending unit.
You found that the PO had not connected the correct wire between the fuel sending unit and the gauge. You also found that you had 12V between each side of the sending unit and the battery (+) terminal. That makes perfect sense. The sending unit is a variable resistor. When connected properly, one side of the sending unit is connected to earth ground and the other side goes off to the gauge. As mentioned above, the variable resistance of the sending unit throttles current flow through the gauge. You determined the "far end" of the wire is not connected to the gauge. When you're measuring between the sending unit terminals and battery (+)... in both instances you're measuring between the battery and earth. A better way to examine the sending unit is to disconnect the green/black wire from the sending unit, put your meter in resistance mode and connect it between chassis ground and the "bare" terminal where the green/black wire was. Move the float arm up and down using a coat hanger or bent wire through the filler neck. Full up should be close to 30 ohms on the meter. When you push the arm down, the meter should show increasing resistance, approaching 270 ohms when the arm is all the way down (empty).
There are numerous reports of NOS Smiths stabilizers being DOA. An acquaintance of mine in Washington State found on one occasion that he had to go through 5 new ones before he found one that worked. For more info on the stabilizer and a way to make your own solid-state replacement, see my PDF:
http://home.mindspri...eStabilizer.pdfThere are usually people on eBay (and elsewhere) who make pre-packaged solid-state replacements. Those are good alternatives (though pricey) if you don't want to make your own. Anyway, with the ignition on and 12V on the "B" terminal, the stabilizer should have SOME output. It's often very hard to read with a digital volt meter as the output of the stabilizer is actually swinging between 12V and 0V as it operates. Someone is bound to post that you need to check the ground on the stabilizer. The symptoms you report do not indicate a ground problem. IF the stabilizer looses its ground, it passes a full, unregulated 12V to the gauges and they read "high". You measured no voltage which implies that the stabilizer's internal points are glazed over or oxidized. Read through the PDF and this will make more sense.
It sounds like the ignition warning lamp portion of your charging system is OK. From your earlier post it didn't sound right. Anyway, it sounds like you're seeing the proper behavior (lamp on with ignition on and engine not running, lamp off with the engine running).
I'd say your next step is to find, buy, or make a new stabilizer for your gauges followed by correcting the wiring mistakes between the sending units and the gauges. I'd still like to see a photograph of the back of your fuel gauge. I'd like to confirm that whoever put your gauge package together is using the bimetallic type gauge and not the early type used before 1965. Since your car is a combination of new and old, it's an area that could have a mistake. The gauges used before the stabilizer was introduced cannot be used with the later sending units... which you have.
