[aerohead]

I left California in 1975 and never looked back.
At that time, the California Highway Patrol could shunt all surface traffic into roadside ' snap-inspection' stations.
They were in possession of emission control hardware for every car sold in the USA, and if what existed under the hood did not jive with what the OEM equipment was, you'd be issued a citation, and given 30-days to bring the car back into compliance with the OEM devices, and pass the 'SMOG' inspection in order to register and tag the car.
I don't know what current policy is within the state.
In the 1980s, carmakers built 'California-only' vehicles for sale within the state, which were the only cars certified by the California Air Resources Board ( CARB ), and the South Coast Air Quality Management District.
Perhaps you could 'chat' with a 'CHIPPY' at a Sacramento Dunkin Donuts, and get some valuable info.