Should alternator be putting out 13-14 volts?

Get a service manual if you don't have one. Download them from MyMopar

The problems can be sort of divided up into sections

1....Bad output circuit especially on later cars. I don't remember if yours has the separate charging line feed -through outside of the bulkhead connector. That is, broken connections, in the bulkhead connector, or even sometimes at the ammeter

2....Problems in the field circuit. Either not enough voltage from the IGN circuit supplying the VR, or a broken wire

3....Bad OR UNGROUNDED VR. They MUST be grounded

4....Bad alternator.

To get started, assuming you have the original style (up through 69) unit with one field wire, hook a clip wire lead from the alternator field terminal to a battery source, like your starter relay big battery stud. Start the engine and monitor battery voltage. Slowly bring up RPM. voltage should climb, alternator should be putting out "full." Ammeter should be hard over at fast idle. Don't let the voltage get above 16V if you can help it.

If this does not happen, either the alternator is bad, or there is an OPEN in the output circuit, otherwise called the "charging line."

So move your voltmeter from the battery to the big stud on the alternator. Bring up RPM. If V is still not "up" then alternator is not putting out much. If voltage is quite high, maybe 18--20 or more volts, then you have an open / bad connection in the output/ charge line

Now IF this test DID show good increase at battery, Next, hook up green field wire "as normal" to alternator. CHECK the VR is grounded "clean and tight" to firewall. If it will not bring up voltage, disconnect two wires at VR and jumper them together. Repeat test as in first test above. If voltage comes up, replace VR. If it stays low, either the green wire is broke, or the IGN (blue) is not getting voltage, broken somewhere.