[POinNJ]

The short story is 68 911 with 70t engine car is still being put back together. Shop put engine in last year but alternator light was on faintly. Charge at battery(new Interstate last year) was never above 11.98 (battery had been drained somewhat while I was testing other circutis, lights, horn etc) no matter what RPM the engine was running at.
I removed the alternator, and checked it according to the 101 project book. It appeared to have open windings, so I ordered a rebuilt replacement. I installed the replacement, reconnected everything. I turned the ignition key on and the alternator light was nice and bright red, I started the car and the light went off. I measured the voltage at the battery and for the first time, it was above 12 volts, slightly at idle. I shut the car off and went looking for my wife so she could increase the RPMs and I could check the battery voltage again. Now I'm back to the same symptoms as before, alternator light on faintly and no voltage above 11.98 despite engine rpm.

Additional points:
1) The voltage regulator is original.
2) I didn't find a ground strap from the alternator to the engine block, so I made one from 12 gauge wire from one alternator stud to the block.
3) I checked for the transmission to body grounding strap and it is good and tight.
4) I bought a replacement voltage regulator based on this part #STANDARD MOTOR PRODUCTS Part # VR124 which is listed as a replacement for a 70T alternator. I have tried this VR both prior to installing the new alternator and after the new alternator. No change in voltage, however the alternator light does not come on at all(with ignition switch on or while running)

Is is possible that the original VR is faulty and the new one is incorrect?