Flickering or pulstating Headlights

Also wouldn't hurt to start with a new regulator (being as you said it wasn't new). The one I mention on the diagram is adjustable so you can set the voltage to anything you want. I set mine to 14.5 volts when the engine is above idle. Makes the lights nice and bright.Also make sure you clean off the paint under the regulator mounting screws so you get a good ground. If this doesn't fix it do what I suggested and you will be good to go.