He's right, engine castings usually say a year before the model year of the car. Which would actually be the true year it was made since car model years start about 6 months earlier than the actual new year.

Here is my date stamp, however I'm positive my ZC is an 88 because I have the 21 spline clutch and that was only around in 88. Thought technically it is illegal for me to have this engine because your not supposed to put an older engine in a newer car.