Nailed by Cali smog

In theory I agree with the maxim that if it is clean at the tailpipe then it should pass regardless of what's under the hood but I think li0nhart123 and David_56 have nailed it on the head so a visual to ensure that exhaust pipes are connected all the way back, no temporary injection systems installed, etc, etc would be appropriate.

What I'd really like to see is some sort of special/seasonal/limited use permitting for older cars. Reality is most of these cars don't see daily driver usage so a special registration to reflect that would make sense. It would exempt the cars for emissions testing in perpetuity and carry stiff fines for violations (over so many miles per year - sort of like insurance companies do) and a reversion to normal registration. I don't know what a good annual mileage would be (somewhere significantly south of 5K I should think) but it could be reported at time of annual registration (like the Auto Club does) and if found to be falsely reported again with the fines and ejection from the program. Alaska has a program like this called seasonal registration (in recognition that some cars are put away for the winter) no emissions testing, reduced cost and good for something like 4-6 months during the spring/summer/fall.