DEA136864 refers to the orig engine stamped number.
Consider yourself lucky, if you still have the orig engine. As kb3csw said, look at the flat flange aft of the distributor. You may need to use a wire brush to clean it up in order to see the stamped numbers. The prefix "DEA" is specific to the "1946" 2nd Design 235 motor. Your block cast number should be 839751. Please also reference Brads41-46chevys.com. Sounds as if your data plate is gone.