Five years prior to the beginning of the story, Bunta started sending a 13 year old Takumi out in the Eight-Six as a delivery driver.

At some point Bunta opened the Fujiwara Tofu Store, turning his car into a delivery vehicle. He used the car to set the fastest downhill record on Akina, with this record still standing by the beginning of the series. He may have used it during his races with his rival, Ken Kogashiwa.

It's unknown when Bunta purchased the Eight-Six, though it is implied that he had used it during when he went around racing with Yuichi Tachibana. History Manga/Anime/Legends Use by Bunta Fujiwara