Those fittings were routinely used on oil pressure lines and fuel lines, along with a female fitting that swaged the tapered tip into the tubing. You'll find a similar fitting in 3/16" diameter used on the oil connector tube on older stovebolt rocker arms, the one from the oil distributor that goes through the water jacket. Ford used that type of fitting on the line from the fuel pump to the carburetor on flathead V8's. Dorman or Weatherhead should have a listing for it if you can find a white-haired old geezer who still knows how to use a paper catalog at an ancient local parts store!
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!