Flickering or pulstating Headlights

I transplanted the entire charging system from the 73 to the 67 so that's where the harness connector came from. My volt gauge needle doesn't twitch.

Well, if the all lights flickered on the stock charging system for a 66 they would not have sold very many. I could live with the volt meter bouncing if the lights weren't . Something is causing the bounce, just have not found it. Thanks for all the input and help!!