Which car company first introduced factory installed and dealer-installed eight-track tape players in cars?

The first major car company to introduce the eight-track tape players in cars was the Ford Motor Company. History specifically notes that the marvels of the automotive music scene made their first appearance in September of 1965, when the Ford Motor Company introduced factory-installed and dealer-installed eight-track tape players in cars as an option in 3 of their 1966 models (the sporty Mustang, luxurious Thunderbird, and high-end Lincoln). Additionally, at that time, RCA Victor introduced 175 Stereo-8 Cartridges from its RCA Victor and RCA Camden record labels, featuring noted artists listed in RCA catalogs.

By the 1967 model year, all of Ford's vehicles offered the tape player upgrade option. Most of the initial factory installations were separate players from the radio, but dashboard mounted 8-track units were offered in combination with an AM radio, as well as with AM/FM receivers. Muntz Car Company and a few other manufacturers also offered 4/8 or "12-track" players that were capable of playing cartridges of either format, 4-track or 8-track. With the backing of the U.S. automakers, the eight-track format introduced by Ford quickly won out over the four-track format.

1978 was the peak year for 8-track sales in the U.S., with sales declining quite rapidly from then on. In the U.S., eight-track cartridges were phased out of almost all retail stores by early 1983. Car companies went to the smaller cassette tape, which was one-third the size.