Ford Mustang E
In 1969, there was one interesting and rare particular version called “E.” This was short for “Economy.” This special version featured the base 250 CID straight six engine, automatic transmission with a unique torque converter, and a strangely low rear axle ratio (via Fox News).
The Mustang E, prepared like this, was an economical machine with excellent fuel economy. But since it appeared in the middle of the muscle car craze, no one paid attention to this economy model. They were interested in high-powered, gas-guzzling models. This is why only 50 Mustangs E are believed to be produced.