Actually I think that's a picture of a 14N, though they look very similar.
And looking at your top photo again, the number of pushrod ports would imply a 14 cylinder engine, so it could be a 14K. (or 14N, and therewere Italian dirivatives as well)
The reduction gearing seems to be missing though. And the entire rear half of the engine is missing. (which is why you must have thought it was a 7-cylinder engine) Had it not been for that pushrod configuration (with all located at the front, instead of seperate rows front and back) it may have been dificult to realize it was a 14-cylinder engine.
(It seems I was pretty close with my initial guess
)
The 14K seems to have coarser and more widely spaced cooling finns, while that of the 14N above match your engine more closely. (as well as the Itialian Piaggio P.XI's cooling finns)
-the 14K mistral major:
and the Piaggio P.XI for comparison
Can you do some measurements on the cylinder? (the bore should be easy enough given the missing cylinders, but you should be able to get a rough estimation of the stroke from the remaining cylinder)