There is no casting number in the usual place by the three threaded holes on that side. I looked at some of the 235 engines I have stored and they have casting numbers in that "pocket" by the 3 threaded holes. Thank You for the help in this matter!
If the "three threaded holes on the side" are for side motor mounts, then your date code would be Jan 23, 1964 as side motor mounts started in 1958.
Post a picture of the passenger side of you engine.
Mike B
