voltage gauge bounces and lights flickering.

My car is a 74 Duster with a 360. I am having issues with the voltage gauge bouncing and the lights flickering. The engine bay has been completely rewired with all new wiring, all of the lights have been wired with relays, headlights are converted to H4 halogen, msd 6al box with blaster coil, and I have done the amp gauge to voltage gauge conversion. The voltage gauge bounces between 14-16 all the time, doesn't matter if headlights are on or off. I have tried everything I can think of from different alternators, new voltage regulators, ground straps from body to motor, motor to frame, body to frame, and even from voltage regulator to body to make sure it wasn't a bad ground. It is driving me crazy because the lights flicker rapidly like a strobe light. Has anyone had this issue or does anyone have any ideas?