Whakaotihia te rerenga e whai ake nei: I te tau 1974, i hangaia e Postlethwaite tetahi motuka hou mo te tiima, te Hesketh 308, i rite mo te Silverstone International Trophy, i wikitoria e Hunt, i tana whakataetae tuatahi i te South African Grand Prix. He kaha te motokā, ka eke ki te tūranga tuatoru i te Swedish Grand Prix, i te Austrian Grand Prix me te
Ko te United States Grand Prix. Mo te tau 1975, i hokona nga tauira o te 308 ki a Harry Stiller Racing, nana nei i tuku a Alan Jones i tana tuatahi nui. I hokona hoki e Polar Caravans tetahi Hesketh chassis, i te wa i whakarerekehia e te roopu mahi te 308 mo Hunt. I taua wā anō, ka tipu a Horsley hei kaiwhakahaere rōpū whai hua, whai pūkenga hoki, ā, i raro i tana tohutohu, ka anga whakamua te rōpū.