[dmsfrr]

If the brass elbows are fitted to both sides the choke heat tube should be in there. They are a snug fit into the ends of the tube, and should twist out if you want to remove them. The elbows likely cover the ends of the tube from view.
If the tube weren't in there the elbows would fall out.

Two photos of a '56 ECZ-A intake manifold with the heat tube, you can see the ends from the outside. You may need a small mirror and a good light?
The tube shows easily on the drivers side of this one as the end is flush with the manifold surface. photo # 1
The passenger side end is recessed a bit but can be seen inside. photo # 2
Just because I could, I inserted a length of 1/8 plastic tubing into it, covered the hole at the other side of the manifold with a finger and blew into the plastic tube with good results. I'm hoping you can do the same.
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