Bill,

Does the side cover run from above the distributor to just under the valve cover (over/around the spark plugs)?

If so, you most likely have a 216 or a pre-1950 235.

If the date casting codes are located on low-pressure 216/235 engines in the same places that they are located on high-pressure 235/261 engines, the head date-casting code is under the valve cover and the block date-casting code is located in an exposed position below and to the left-of the distributor (locations on high-pressure engines are shown here).

Tim