There are varying levels. 75 or older you never have to do an emissions test if you run "collector" plates. 76 to 84 (I'm not 100% certain about the 84) you have to get an emissions test once if you keep it with collector plates.Here in Nevada if a vehicle is 25-years or older yo can get a ""classic vehicle" registration that does not require a smog check. You would figure every state would have such an option for vehicles that are too old to find parts for.
Used to be there was a 25 year thing, but I believe that's no more.
I figure that's the only way I'll be able to keep the crew cab if our area has to test.Makes me wish I kept the Vin tag from my 75. Still have the title. Could've done a little swapping to the 91.