amp meter needle is crazy

If you have a wire from the battery post of the alternator going to the ammeter and to the starter relay stud, you are still seeing too much amperage to the ammeter. The bulkhead alone is a shunt that maxes at about 55 amps. Bypass the ammeter and get a voltmeter.

I had North Hollywood Speedometer turn my ammeter into a voltmeter. Face looks the same just has VDO movements on the back.

What is the voltage re a ding at idle and above idle at the battery and at the alternator post?