Flickering Lights
OK, this could be in the ignition harness, a poor regulator ground, or the regulator itself.
To temporarily eliminate the harness, take a BIG clip lead (you might have to build one out of no12 wire, and should have one, anyway
Unhook the regulator IGN terminal, and temporarily hook direct from the battery + post or the starter relay stud to the IGN terminal on the regulator, and see if the problem "goes away." If it does, you have a drop problem in the ign harness, probably in the bulkhead connector, the ignetion switch connector, or the switch itself
If not, run a ground wire from the regulator mounting to the engine block or the battery ground, see if the problem goes away
If neither of these procedures fix the flickr problem, unhook your alternator field wire at the alternator, and clip from the battery + to the field terminal. Run the engine, adjust the idle screw until the ammeter JUST shows a little charge, and play with heater, lights, etc, to check for flickr. IF it is OK,
replace the regulator