 Nyorai kupfuurira kweiyi ndima - Muna 1954 na 1955, Gregory akakwikwidza mumakwikwi eEurope, kazhinji kazhinji achityaira Ferraris. Nhoroondo yake inosanganisira Tourist Trophy kuDundrod uye Maawa 24 eLe Mans kunyange zvazvo mutyairi wake Mike Sparken akasiya basa Gregory asati awana mukana wekutyaira. Akakundawo Nassau Trophy yokutanga paBahamas Speed Week muna 1954. Achidzokera kuAmerica muna 1956, Gregory akapinda mumakwikwi anoverengeka eSCCA, kazhinji achikunda. Muna 1957, akaedzazve kumhanya muArgentina makiromita chiuru, panguva ino akahwina. Kuita uku kwakamuwanisa mukana wekutyaira neGuglielmo Deis Scuderia Centro Sud, timu yeFormula One inoshandisa Maserati 250F. Mujaho wake wokutanga wakanga uri muMonaco Grand Prix ya1957, kwaakawana nzvimbo yechitatu inoshamisa, nzvimbo yokutanga yeAmerica muF1 Grand Prix. Akatevera ikoku nenhevedzano yemigumisiro yakanaka, achiuya wechisere muGerman Grand Prix, uye wechina muPescara neItaly Grands Prix. Pasinei zvapo nokukwikwidza bedzi muhafu yemijaho, Gregory akapedza mwaka wa1957 ari panzvimbo yechitanhatu mumakwikwi. 