I am old enough to remember cars without catalysts and they did not smell with the gasoline of the day. Now, when I run my older non-catalyst cars (vintages 1966 to 1972) they smell from the gasoline. There are no exhaust leaks and the carburetors don't leak. Even tweaking the mixture to run a bit lean is no help. So can anyone tell me why the smell is only on cars without catalysts? Did the government make the refiners add something to the gasoline so that non-catalyst cars would smell? I used to use "normal" 93 octane fuel that I use in my daily drivers, then I switched over to ethanol-free gasoline hoping that the smell would go away. It did not. Is there any additive available that would diminish the odor? Thanks