If it's got a 1/8" diameter tube, it's the only stovebolt vacuum advance in the world like that. The original vacuum line was 3/16" OD. Can you post a picture of the unit you've got, showing good detail on the threads?
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!