ɪn nˈaɪntiːnhˈʌndɹɪd sˈɛvənti fˈoːɹ, ðə sˈɪɹiz θɹˈiː wʌz ˌɪntɹədˈuːst, wɪððə mˈeɪn tʃˈeɪndʒᵻz bˌiːɪŋ tə ðɪ ˈɛndʒɪn kəmpˈɑːɹtmənt, tə kˈiːp ɪn lˈaɪn wɪð nˈuː nˈɔɪz lˌɛdʒɪslˈeɪʃən.
In 1974, the Series 3 was introduced, with the main changes being to the engine compartment, to keep in line with new noise legislation.