The largest production twin engined motor scraper to be offered by any earthmoving equipment manufacturer, the Caterpillar model 666, was introduced in 1962 along with a raft of other ‘600 series’ motor scrapers that Caterpillar had been developing. Boasting a whopping 54 cubic-yard-heaped bowl, the 666 was also offered as a single engined scraper, which was known as the 660.