Toyota Motor Corporation's M family of engines were a longitudinally mounted straight-6 engine design. They were used from the 1960s through the 1990s. All M family engines were OHC designs. While the M family was born with a chain-driven single camshaft it evolved into a belt-driven DOHC system after 1980. All M family engines used a cast-iron block with an aluminum cylinder head, and were built at the Toyota Kamigo plant in Toyota City, Japan. The M-E variant, available only in the Japanese domestic market, was the first Toyota engine to be equipped with fuel injection (around the same time as the 4-cylinder 18R-E). The 4M-E was the first Toyota engine to be equipped with fuel injection for non-Japanese markets. The M family were Toyota's most prestigious engines (apart from the uncommon V family V8) for over 30 years. They were commonly found on the large Toyota Crown, Mark II, and Supra models.