Having said that, I am reminded of a story conveyed to me when I did an engine swap many years ago. It illustrates the incongruity between some of the California Smog requirements.
This guy did an engine swap into a late '60 something (smog controlled at the time of the swap) Ranchero. He used the entire 5.0 power train from a '90 something Mustang GT. Smog regulations require all the original smog equipment from the 'Stang be present on the Ranchero. So he ran dual exhaust with two catalytic converters, exactly like the 'Stang. When tested it's emissions levels were way under the limits for the strict '90 something year of the engine. However, it failed the visual inspection because of the catalytic converters. Seems, smog regulations will not allow retrofitting a car with catalytic converters. Why? No one at BAR could give an answer. So the cats were removed and the Ranchero retested. It now passed the visual inspection just fine, but it pumped out multiple times more emissions. Failed, right?? Wrong!! Turns out it only had to meet the standards of the year of the Ranchero. Which it just barely did.
Go figure...