I'm going to take a swag: The engine has the water pump completely in the block which would indicate a 55 or later 235 (or 261). The cast number appears to be a date code G 9 8 = July 9 1958. If that is correct then a later motor was swapped in at some point. The absence of a stamped serial number might mean it was a replacement/ service block. I also saw the 3-speed shifter box on the column. Where is the shifter? Is there a hole in the floor for the clutch pedal?
That poor motor looks sad. You DO have your work cut out for you. There are still lots of 235's out there. A correct 54 might not be too hard to find. That one may/may not be salvageable.
Good luck.

Professional Novice