Re: Headlight/high beam question - 1967
You may simply need to replace the outer ( closest to fender) bulb.
The outers have (2) filaments, one for hi and one for low. If the hi filament is burned out, it would make the bulb "dead" only when HI's are activated.
To verify, take a test light and probe the light green wire on the suspect bulb, if it has 12 volts when HIs are activated and the ground is good, it's a bulb issue OR a dirty socket.
-If you don't stand for something, you'll fall for anything.