It's a after market road draft tube. I've never seen one like this either but that's what it is. Somebody's better idea. And for those that arn't familier with what a road draft tube is they were standard on all cars up until about 1962-63. Their purpose was to suck fumes and gasses from the crankcase. They were done away with when engine manufactures were mandated to no longer pollute the planet. That's when PCV valves cam into play. Basicly the first form of smog control.
Chris you were the only brave soul to venture a answer so why don't you ask a question?
BB