The lights flicker a bit on my 66, my 70 not as noticable if at all. I just chalk it up to 50+ year old electrical system and connectors. I did replace the voltage regulator once upon a time with a electronic version but when the regulator case wasn't properly grounded the system overcharged, burned out my ammeter, boiled the battery dry, and blew a bunch of light bulbs out. When I fixed all the damage and put the original points type regulator back on all has been good.
