Interesting. I have seen some people ask about catalytic converters for getting rid of the “old car smell” that comes from the unburned hydrocarbons etc. you get with the older carbureted engines. Personally I like the smell, but of course it’s carcinogenic too. And people that have a 2-story with a bedroom over garage layout might not appreciate it as much either.
The issue is that on carbureted engines the catalytic converter’s tend to foul pretty quickly, they don’t deal with the extra fuel in the exhaust or lower exhaust temperatures as well. It would obviously be different on a classic that had a modern engine swapped in, although depending on your modifications you could just use the converters that would be right for that engine. And running EFI would also solve that issue, although again that would also open up more converter options too.
