Yes, every time I'm behind or passed by a "classic" older car with carburetors, even one that has been restored and looks like new, I'm surprised by how clearly I can smell the exhaust. By contrast modern cars emit almost no detectable smell. Hard to belive that pre-1980s all cars had exhaust odor like that, I certainly don't remember it from my childhood.
Pre '75 there was nothing to control oxides of nitrogen, which smell pretty awful, and combustion was never clean enough back then to control volatiles and hydrocarbons. I think all they had were secondary air injection, which was prone to failure and subsequent removal
You may not remember the smell, but do you remember the color of the L.A. skyline?
I guess the average carbureted vehicle on the road today is being run by someone with the mindset that the engine should run great and develop lots of power. Back in the day more people would have set them up leaner.
The ideal air fuel ratio for gasoline engines is 14.64:1. It hasn't changed. Running an engine too rich wastes fuel and reduces power, too lean causes detonation and can destroy it. Electronic fuel injection more precisely meters the fuel which keeps combustion closer to ideal. Carbureted vehicles are generally tuned as close as possible to ideal but it's always better to go slightly rich than slightly lean.
