Sure sounds like the alternator isn't producing what it should. Possibilities include
Belt not tight,
Open winding (there are three in the rotor and 3 in the stator)
Bad diode.
Don't believe everything you read.
Some of the problems people blame on the ammeter are caused by high current uses (like running a winch), or actually wiring issues ( like wires rubbing through insulation).
Some years do seem to have occasional problems. 66 does not seem to be one of them.
If you want to do a quick test of the ammeter:
Key off;
Turn on the parking lights. Should see about 4 amps discharge.
Turn on the headlights, Should see about 8-11 amps. (This amount will depend on the lamps installed and whether a 66 Barracuda has the front parking lights on when the headlights are on.)
Sure seems like alternator.
For a home brewed battery load test, clip the voltmeter to the battery and hit the starter.
General rule of thumb (from the SUN VAT 40 instructions) is a good battery should stay above 9.6 Volt.
67Dart273 outlined tests you can do for the alternator. Just follow that.
No. The ammeter tell you how much current is flowing through it. IF you see 40 amps (max scale) flowing through it, then stop what your doing because that much current will damage wiring and connectors.
Its the high currents that damage things.
Which harness and what do you mean by 'block'?
