Voltage regulator

You can use a 70/ later alternator--which has BOTH field connections isolated from ground, correctly called "isolated field," often INcorrectly called "dual field."

You have to add one wire to the 70/ later regulator

---OR---

BUT You can buy 69/ earlier regulators, MOST of 'em nowadays, even though they look similar to original, ARE solid state.

Use ONLY Echlin VR-1001, or Standard (Blue Streak) VR-128. Many others are, well, junk

Easy way to tell on the 69/ older if it is modernised electronic or old school mechanical, is look underneath. Mechanical ones will have one or two big wirewould resistors underneath.

Simplified wiring diagram posted in links at end. Basically you need to run switched 12V to the second field terminal. Existing "green" from regulator to field can be re-used if in good shape, as can the IGN feed to the regulator.

ONE THING YOU NEED TO DO with ANY charging system, especially now that you are "on" it is CHECK charging voltage. With engine warm (to warm regulator) check voltage across battery at a good fast idle. Should be 14V optimum, 13.5-14.5 OK. Turn on all loads, you might have to increase engine RPM to simulate "low cruise." Voltage should not drop below 13.5 on a charged battery.

If voltage is HIGH with no loads turned on, check your HARNESS for voltage drop, and the GROUND circuit.

To check the GROUND, with the engine running as above, stab one probe of your meter, set to "low DC volts" onto the battery NEG terminal.

Stab the other probe on the regulator mounting frame, and be sure to stab through any paint, rust, chrome. You are looking for a very low reading, the lower the better. Anything over .2V (two tenths of a volt) means the ground circuit needs attention. Battery to block--to body.

To check for HARNESS drop, shut off the engine, turn the key to "run." engine off. Stab one probe onto the battery POS post, and the other onto the IGN feed to the regulator or coil resistor.

Here again, you want a low reading. Over .2V (two tenths) try to improve things, .3 or more, work harder, and anything approaching or over 1/2 Volt or more, get SERIOUS

Remove inspect, repair, or bypass the bulkhead connector. Check the entire circuit path from

BATTERY -- FUSE LINK --BULKHEAD CONNECTOR -- AMMETER CIRCUIT -- IGNTION switch connector -- THROUGH the ignition switch -- BACK OUT the IGN switch connector -- BACK OUT the bulkhead connector on the DARK BLUE IGN "run" wire

Anywhere along this path can be one or more bad connections, including the switch itself.

A voltage drop here will cause OVERcharging by the amount of the drop, IE the regulator can be doing it's job at 14V, but if you have a 1/2 Volt drop in the IGN harness, that 1/2 volt will be ADDED to the charging voltage, and same for the drop in the GROUND side of things.

Some reading:

http://www.mymopar.com/index.php?pid=78

http://www.mymopar.com/downloads/Dual_Field_Alternator_Wiring.jpg

http://www.madelectrical.com/electrical-tech.shtml

from the above link, especially THIS:

http://www.madelectrical.com/electricaltech/amp-gauges.shtml