dsc46246.jpg

Close-up where the regenerative cooling tubes become bifurcated.

Also note that F-107-1 is displayed with no injector, offering a view of the aft face of the LOX dome.

Vince Wheelock speculates that, as a test engine, this F-1 was torn down at some point in its life and when it was reassembled, the injector was not installed (and perhaps became a display piece on someone's wall).