Ford’s trick to get around emissions regulations with the 1975 Ford T-Bird was both brilliant and stupid

Today, emissions standards are both well-defined and strictly enforced. But go back to the 1970s, and cutting car emissions was still a new art that automakers were just starting to get to grips with. That led to all sorts of ingenious solutions, and Ford’s was particularly brazen.

This story comes to us from Rare classic cars and automotive history, YouTube channel that covers car stories from years gone by. A new video shows Ford’s bizarre solution to meeting 1975 emissions standards on a tight budget.

How was it covered? New York Times in 1975, Ford had just decided to introduce catalytic converters to all of its models. All of its large full-size V8-powered vehicles had dual catalytic converters, just like today’s vehicles. However, in the case of the 1975 Ford Thunderbird and Lincoln Continental Mark IV, the Michigan automaker found a sneaky workaround.

Why not just one?

There were two main approaches to placing catalytic converters in large V8 vehicles at this time. GM decided it could only use one large pancake-shaped device. It combined the exhaust manifolds from both banks of the engine into one pipe, which fed one large catalytic converter. Ford, on the other hand, used a more modern approach in the LTD, Grand Marquis, and Lincoln Town Car. Each bank of cylinders had its own catalytic converter near the manifolds. This made sense for cars with dual exhausts.

Of course, it was expensive because Ford had to install two catalytic converters, which wasn’t cheap. The 1975 Ford Thunderbird and Lincoln Continental Mark IV had to make do with one catalytic converter, which certainly saved a lot of money. But the cheeky part was this. Ford only attached it to the driver’s side cylinders. It simply wasn’t there for the passenger side cylinders!

If you know anything about modern cars, you’re used to seeing dual catalytic converters on V-engined cars with dual exhausts. The entire exhaust stream has to pass through the catalytic converter to pass modern emissions. Apparently, that wasn’t the case in 1975. Ford was able to sneak past these models, still meeting emissions standards, while only passing half the exhaust power through the catalytic converter!

Interestingly, there was an H-pipe connecting both sides of the exhaust. However, it was after the catalytic converter, not before. In this way, the exhaust from the entire cylinder bank was largely not cleaned by the catalytic converter at all.

This choice had its advantages and disadvantages. On the one hand, Ford saved a lot of money. Catalytic converters were never cheap, so using one instead of two is naturally much more cost-effective. On the other hand, the cars still had one major drawback. They still needed unleaded petrol so as not to poison the single existing catalytic converter.

After all, you’d never get away with it today. Modern emissions standards wouldn’t even allow you to run one cylinder of the engine without running it through a catalytic converter. The carbon monoxide and nitrogen oxide emissions from the untreated exhaust stream are simply too high. But in 1975, you could get by by simply cleaning up half the power of the V8.

It really was a different era. Today we are fortunate to have cleaner cars and nicer air. Still, it’s funny what Ford was willing to do in the bad old days of the 70s.

Image Sources: Rare Classic Cars & Automotive History via YouTube screenshot