Nothing like an oldtimer at the parts counter to get things done! That type of fitting was very popular in the 40's and 50's- - - -Ford even used them on fuel inlet fittings for carburetors, IIRC. They're also used to seal the through-the block oil line on the splash-oiler 216's and 235's.
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!