Do a search on the topic. There was a post a week or so ago that gave wiring diagram options if you want to change your headlight switch to make the parking lights stay on when the headlights are switched on. It is normal for your car to turn off the parking lights when the headlights go on. They are Parking lights which were originally intended to illuminate the car while it was parked by the side of the road in the evening. Their function was changed when emergency flashers became a standard item. A humorous anecdote: When I first took my 65 to state inspection about ten years ago, they wanted to fail me because the parking lights didn't stay on when the headlights were turned on. I argued with the young inspection official and he was getting angry until an older guy walked over to him and told him to pass the car. I don't take the Chevelle to inspection anymore because it has Historic plates and registration, but if you have to take yours, make sure you have some kind of explanation or find an old time inspector.