>As far as '66's being "changed" to '65's, how exactly is that done.
I may have been involved in this situation as I had both a 65 and 66 when the smog laws came into effect.
The 65 was first and I thought was completely stock. I had no idea that there was a snorkel extension that was bolted to the RH exhaust manifold that warmed the air. My car failed and the tech described the part that I needed...fortunately I was able to find one at Pic-a-Part for a few dollars (this was before the mad rush to get smog parts). Ford wanted about $100 for a new one, which would have been painful.
The smog tech knew I had a 66 and gave me some helpful hints.
There was no way to determine if the car came from out of state which did not require the thermactor, only the cars sold new in CA required the smog pump. The rules from CARB instructed the tech to look for empty brackets or evidence of removed equipment. To mimic an out of state vehicle the all the equipment had to be removed, the pulleys replaced and the engine repainted. Once this was done the car could be taken for a smog check and it would pass the visual as well. The snorkel extension was the hard part, but could easily be shared between cars
A few years later the 65 was completely exempt. I sold the 66 and it was shipped to AU.