ðɪ ˈɛndʒɪnz wɜː bˈeɪst ˌɔn ɐ wˈɑːlsɛli ˌoʊvɚhˈɛd kˈæmʃæft dɪzˈaɪn jˈuːzd fˈɜːst ɪnðə nˈaɪntiːnhˈʌndɹɪd θˈɜːɾi wˈɑːlsɛli hˈoːɹnɪt ænd sˈʌbsᵻkwəntli jˈuːzd baɪ ˌɛmdʒˈiː ɪnðɪ ˈɛftˈaɪp bˌʌt sˈʌbdʒɛkt tʊ ɐ mˈeɪdʒɚ ɹˌiːdɪzˈaɪn.
The engines were based on a Wolseley overhead camshaft design used first in the 1930 Wolseley Hornet and subsequently used by MG in the F-Type but subject to a major re-design.