When I bought my 1965 Newport in CA in 1991, you had to get an emissions inspection whenever a car was sold, at that least vintage in that county. The report showed very low emissions, indeed it would have passed the limits for my 1982 Aries. They didn't test NOx then, and emissions controls then messed up HC and CO in trying to control NOx. The later 3-way catalysts fixed that and are much superior.
I recently bought a 1964 Valiant in CA and didn't need an emissions test. I don't know if the laws changed, or 60's cars are so old now they get a free pass. I recall reading that studies showed classic cars are generally well maintained, infrequently driven, and aren't a significant air quality issue. I suspect that an 80's car with failing engine control components would be much worse, and nobody can maintain those vacuum clap-trap setups. Of course, when people put thumper cams in classic cars, they can gas everybody within 50 ft of the tail-pipe.
When I lived in FL in the 1970's, you had to pass state safety inspections. I spent a lot of time and money trying to pass the brake test with my 1969 Dart. The brakes had just been rebuilt and were fine, but the machine showed more braking force on the left. That was a common problem, and usually due to just the driver's weight. Later studies showed that most accidents were caused by idiot drivers, not poorly maintained vehicles, so FL dropped those very unpopular tests.
