Bill,
I had the opportunity to look closer at my records this morning and found the following first date of production for the Thermactor cars:
67202 - Tuesday - May 16, 1967: 02584, 02585, 02586, 02587, 02588 and 02703
67203 - Wednesday - May 17, 1967: 02543, 02589 and 02590
67212 - Tuesday - May 16, 1967: 02546, 02591, 02594, 02595 and 02659
67213 - Monday – May 15, 1967: 02466, 02467 and 02666
Since the motor in 02584 was replaced in the early 1970s, I cannot give you any information on the heads. Hopefully someday someone will reunite the motor with the car, though probably not in my lifetime.
Hopes this helps you in your research,
Dennis