The position of the water pump in your photo indicates that the engine is no older than a mid-year 1955. 54 and early 55's have the sane water pump as a 216, located just below the thermostat housing. If you can see the area near the oil pan rail on the generator side of the engine, if there are two large pipe plugs (1/2" NPT), you have a 1959 or later block that can be set up for full flow oil filtering. The casting number opposite the generator location is the best way to get a correct identification.
Jerry
