I once lived near an inspection station in Texas. I could see what looked like something from the 1930's in the bay they used for tail pipe tests one day, so later I asked the owners about it.

So... Some guy had just rebuilt his 1938 Ford and was tooling around in it and pulled in for some gas. They had just installed a new sniffer or upgraded the software or something so they asked him if they could try their new sniffer on the Ford. Since these guys were a bunch of gearheads they had often wondered just how dirty the old cars were.

The Ford passed the state of Texas emissions test for new cars, and I think this was in 1992 or so. The station owners contacted the state to see if something was wrong with their machine and they were told that due to the long stroke of engines from the 1930's and 40's that many cars from that era could pass the test.

The problem was that they could not develop much power. Having owned a 1938 Dodge at one time I can attest to the fact that the power in these engines is not what you would expect today.

It's a vicious cycle. More power comes from higher compression and that needs higher octane gas and that causes more... Anyway, I am glad that the auto industry has been able to provide us clean engines that put out the power they do. Sadly, it took the EPA holding their feet to the fire to make them do it as fast as they have.

An executive with a well known diesel engine maker told me they had cleaner engines ready to sell, but until their competitors came out with one why should they sell theirs? "Why change the hook if you are still catching fish?", was the way he put it.

That was in 1965. Yeah, I know. I'm old.