148 hp and had a 6 cyl. engine, while the 1468 had 146 hp and a v8 engine. In 1964, IH made its four-millionth tractor, an 806. In 1965, IH introduced its first two-wheel-drive tractor, the 1206. Another option became available in 1965 for the 706, 806, and the new 1206: a factory-installed cab (made by Stopler Allen Co.), often called the "ice cream box" due to its shape. It could be equipped with a fan and heater. By 1967, over 100,000 models 706, 806, and 1206 were built. The 276 was also built at this time, becoming popular for smaller farms with tighter lanes and fields due to its lighter weight. In 1967 was the introduction of the bigger and more powerful 56 series tractors as replacements for the popular "06" series. These new models included the 656, 756, the 856, and the 1256. The "ice cream box" cab was still an option. In 1969 IH introduced the 1456 Turbo at . Also that year, the 826 was introduced with the option of gearshift or hydrostatic transmissions. The "ice cream box" cab was dropped and replaced with a new "custom" cab made by Exel Industries which could be equipped with factory air-conditioning, heat, and an AM radio. Another milestone was the 1970 introduction of the 1026 Hydro, basically a hydrostatic version of the 1256 and at that time the most powerful hydrostatic transmission tractor made in the US with . 1970s In 1971, IH introduced the 66 series line. The new models included the 766, the 966, the 1066 turbo, the 1466 Turbo, and the 1468 V-8. The 4166 4WD was also introduced. The 966 and 1066 were available with Hydro or gearshift transmissions and the choice of two-post roll over protection structures (ROPs) or two different cabs, the "custom" and the "deluxe". Both could be equipped with air conditioning, heat, and AM-FM radios. In 1972, the 666 replaced the long-running 656, the 1568 V-8 replaced the 1468, and the 1566 and the 4366 4WD were introduced. Also later that year, four-post ROPs replaced two-post; the "custom" cab was dropped and the "deluxe" cab was now painted red instead of white. Due to horsepower confusions, the 966 and 1066 Hydro models were restriped; the Hydro 100 and the 666 Hydro became the Hydro 70. On February 1, 1974, at 9:00 am, the five-millionth tractor came off the assembly line