I have the door plate and the DSO was 71 but i believe the car was ordered to send to Arizona?
The DSO would be 75 if it was an Arizona ordered car. All 1966 Fords ordered with DSO 71 and 72 were required by California law to be equipped with smog equipment. (The same smog equipment applied to all new 1966 cars from all manufacturers.) There are a couple of "quirks" in the law which states "sold in California after January 1, 1966", but Ford put smog stuff on all California cars from August, 1965 anyway. For some reason, 66 HP engines were exempt as well (thankfully).
I will look at the heads once i have a spare minute to remove the rocker covers i will get back in touch with details
Your VIN indicates a May, 66 build which may (pun not intended) have one of two types of smog heads. The early type have an air injection port for each cylinder, and would be obviously "plugged". The type used in 67 has a single port at the LH rear or RH front. I'm not sure if the 67 type can be made non-smog, a "plug".
At this stage, you might want to verify the engine assembly date. It's located on a casting extension, called a boss, on the LH front side near the distributor. A bolt from the water pump goes into the "boss". The format is, year (single digit), month (a letter), one or two numbers for the day, and a letter, assembler or inspector. Yours should look like "6CxxZ" or "6DxxZ".
Jim