Voltage regulator location? Need a new alternator?

The regulator is the "black thing" at the bottom right of the photo

What you need to do:

Identify the IGN terminal on the regulator which is the "push on" flag terminal and not the screw terminal. "Rig" a voltmeter from that point --without disconnecting it---and hook the other probe to the POS post of the battery. With the key in "run" and the probes connected, you are hoping for a very low reading, and "I bet" you get over 1 volt. Post back what you read. That reading indicates voltage drop. Any reading more than .3V or so (3/10 of one volt) you should investigate.

The functional path is battery---to starter relay "big stud"---through fuse link--------to bulkhead connector on "big red" ammeter wire------to and through ammeter---out ammeter on big black ammeter wire---to welded splice. ----Branches off to ignition switch connector---to and through switch---out of switch connector on dark blue IGN1 "ignition run" and back out through bulkhead connector----to ballast resistor (the long white ceramic block nearby)---------and splits off to feed the voltage regulator ---------Any and more than one of the points mentioned can have a loose/ bad/ corroded connection and ADD voltage drop which will cause OVER charge voltage

====================================

You must also test the GROUND side of the circuit. This is similar but a bit different. Get car running on fast idle, with battery "up and normal" and run the following test first with all accessories off, and again with heater, lights, whatever you can bring on activated.

So with the engine running as above, stab one probe of your meter directly into the battery NEG post. Stab the other into the VR mounting flange, HARD to get through rust, paint, etc. You are hoping to read very little, the lower the better, and zero V is perfect.

=====================================

IF it turns out that both of the tests above test "OK" (Readings less than .3V) then make sure the battery is charged and try a different, known good battery. Don't buy a new battery, that is, try one you have if you do......... If THAT does not cure the problem.........replace the regulator
====================================

REPLACING THE VR..........The one you have is a 69/ earlier system. All new VR's for that system that I'm aware of are actually solid state internally--an upgrade. But you could ALSO convert that to a 70/ later system BY ADDING ONE WIRE. That is because the alternator you pictured is a late model "isolated field" and the "square" diode pack is called a "square back". That is a better design than original.