I could not even find this in the 66 or 67 shop manuals, and I can never remember "from one time to the next" but SOMEWHERE on the lock cylinder, there's a pinhole. There is always a trick, sometimes you start with it in accessory, or on, etc, depending on the car, but you get it to some point, and you can depress the release pin with a paper clip, etc, maybe give it a turn with the key, and the lock will slip out