It's just screwed into the manifold.
I would think that it would unscrew, but 60 years of heat fluctuations have bonded it to the manifold.
Also, none of my wrenches fit it. (go figure) It seems to be rather brittle, too, because my Vice-Grips remove material from the fitting.
I'm sort of thinking that I need to go and get a new piece of hose and find something to block up the end.
