I was just told about this Ford factory 8 track player for Mustangs, Galaxies, and Torinos that plugs into the Ford AM radio, and mounts between the dash and shifter console

https://www.ebay.com/itm/1969-Ford-Am-Stereo-Radio-8-Track-Tape-Player/173175894466

https://www.ebay.com/itm/1969-Ford-8-track-tape-player-Galaxie-Mustang-Torino-tunnel-mount-1970-1971-rare/173168755430
https://www.ebay.com/itm/NOS-Ford-1969-70-71-Galaxie-Mustang-Torino-radio-and-8-track-player-kit-RARE-/202168505306
http://www.autopartsobsolete.com/1968-69-70-ford-8-track-player-original.html

if you want to see factory 8 track players in Pontiacs and Chevys, https://www.kijiji.ca/b-saskatchewan/8-track-players/k0l9009