JoelW

Hello Mustang fans,
I am a student doing research that involves data from smog tests from the state of California.

While doing basic "does this make sense" tests, I noticed that there are almost no 1978 Mustangs in the data. There are significantly more 1974-1977 Mustang models (10-20x as many in each of these years as 1978), which is the same variety of Mustang, and many times that number starting in 1979 with the "New Breed" models.

I am trying to figure out why this might be the case (other than: the data set is bad!).

It doesn't seem that 1978 had significantly fewer Mustangs produced, though How Stuff Works does mention a "temporary emissions-related regulatory snag." Perhaps the details of this explain the discrepancy.

Is there a smog test regulation in California that would make people particularly unlikely to have 1978, as opposed to 1977 or 1979, Mustangs?

Thanks for any help.

Best,
Joel

roystere

Hi,
I have a 1978 Mach1 that's been modified with a 5.0 EFI motor out of an '86 Mustang. I had to smog it to register the car in California. It was smogged once at the state referee station then I put Historic Vehicle plates on the car so that's why my car doesn't show up in the data. I have a friend in Placer County who has two, but I don't think he has to smog them. Good luck on your research.

JoelW

Thanks for the information. You bring up a good point- maybe most 1978 Mustangs don't have to be tested in CA, which is why I don't see them. However, in general cars in the 1970s are not exempt from emission testing- I see plenty of Mustangs of other years. I'll have to look into it further.

vonkysmeed

Here in California, anything 75 or later are not exempt from smog. With that said though, it does not mean that earlier cars are not tested due to the engines in the cars.