Finally replaced the external voltage regulator with a new one. The voltage output is stable, I'm getting 14.5v on idle and on any RPM, with loads on it maintains over 13v which is good compared to the old one where it would fluctuate 12-13v and sometimes drops under 12v under heavy load!
BUT! The damned flickering lights is still there. The dash lights, headlight or any lights would flicker whenever there is a load on the electrical - fuel pump, turn signal, headlamp, etc. What else could cause this other than the alternator and the regulator? Alternator is pretty new, I can't remember how old but less than 5 years old IIRC. I've took the alternator apart few weeks ago to clean the mess (damn PS fluid leak - deleted the PS already lol), and I can't see anything wrong with it.
My wiring is fine, or at least I thought it is, new 4ga grounds from the battery to the body, 8ga from the alternator bracket and valve cover to body and fused 8ga positive wire from alternator to the battery. I even replaced most corroded wire/connectors few months ago. Newish battery, even tested with a known good battery.
Is there anything else I'm missing?
BTW whats the function of condenser?