1964 Plymouth Barracuda headlight knob won't pull out from dash

you should consider an "upgrade" at this point. Install a relay to power the headlights. Full amp draw goes through the light switch in the dash. People make the mistake of putting in brighter (more wattage) bulbs. This higher draw is a problem. Many a mopar has been set on fire by these switches shorting out on the higher amp draw especially as they age. Its easy to do. MUCH safer and you'll have brighter headlamps too. IMHO