Older headlights have a bad habit of losing the reflective surface on the back of the sealed beam. Most of the light goes out the back of the bulb instead of being reflected and focused through the lens. Also, the voltage regulator needs to be adjusted for a terminal voltage of 7.5 volts at the battery with the engine running at fast idle. There's nothing wrong with a 6 volt system if the connections are clean and tight, and the regulator is adjusted correctly.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!