62 Valiant 200 / 170 cuin /6 - Odd smell - then dead battery

Yup. When there is just 12 Volts at the alternator output and the battery with the engine running, then the alternator is not producing power.

You could remove the ground jumper you installed on the brush and then measure resistance from each brush terminal to the alternator housing.
Should be infinate resistance. if not maybe one of the brushes was grounded by using a metal washer.

If its on the car now, I think I would check for voltage at the regulator's power connection (sometimes marked IGN). That should be connected to a blue (J2) wire.
And if the feed is at system voltage, then check the voltage on the regulator's output terminal if that has voltage.
> If there is no voltage, then the fault is likely in the regulator. Points type remove the cover and look for melted links (fine wires)
>>If there is voltage, then check at the field connection on the alternator. This will reveal if there is a break or a short to ground in the wire.
>> One other way to check for regulator problem, which might not be revealed just be voltage, is to bypass the regulator. Best to do this at slow idle. All you need is a jumper wire with aligator clips on each end. When bypassing the regulator, remeber that voltage will increase with rpm. Not a good idea to drive around like this.