The Rover-Landers of BC

I was cleaning out my spares area and came across this Gooseneck Exhaust. When you rotate it there seems to be something moving inside. Maybe a primitive exhaust brake? There are teeth on it for a ratchet or something.

https://i.imgur.com/5BNA2lcl.jpg

Would that be something installed by the previous owner or factory?

I think its a deflector to heat the intake on low flow, but when the flow gets high it opens fully to not restrict the exhaust flow.

Yes, it’s an intake manifold heater. Helps with cold running. When things heat up, it’s supposed to close and stop diverting the hot exhaust around the intake. I’ve never seen one in person, but it seems like one of those good ideas that probably doesn’t work all that well (especially after 55+ years).