Overcharging 73 Swinger

You should learn to troubleshoot instead of throwing parts at it. I mentioned that the alternator field terminals should show NO continuity to the case (ground) or in other words, both should show infinity. You can easily check that with a meter, or a "quick" check with a test lamp.

Why isn't your new alternator charging? Lets try some actual troubleshooting. You have tools?

You need a 12V test lamp, a couple of alligator jumper leads, and a multimeter at minimum.

For starters, "quick check" try this: turn the key to run. Don't leave it that way longer than necessary to make these tests.

If you have no meter, with the key in run, disconnect the green wire at the alternator. In subdued lighting, you should see a small spark there as you disconnect or reconnect the wire. If not, take a jumper wire or screwdriver, and with the green field wire disconnected, ground that exposed alternator terminal. You should see a small spark.

Now check for voltage on the blue wire. use a meter or a test lamp, but with the key in "run" the blue wire should be "hot" same as battery.

If it is, recheck the alternator. Check with a test lamp with the blue connected, and the green disconnected, check the terminal where the green was connected. Should get a light

Another thing to try AFTER you have varified you have voltage on the blue wire, is to jumper the field terminal where the green connected to ground. Start the engine and slowly bring up RPM. Ammeter should show and increasing charge.

If not you likely have a defective alternator. "New" does not mean good (functional)
Ok. Ran through all of this. No spark with the green wire but terminal has B+. Green wire has continuity from end to end. Ground Field terminal and system operates as designed. My thought is a faulty VR or poor connection at the regulator.