1989 was the first year where naturally aspirated engines were compulsory for all teams after the banning of the turbocharged units at the end of the previous season. To this end, Honda built a 3.5-litre V10 engine, developed throughout most of the latter half of 1987 and through 1988. The MP4/5 was unveiled for pre-season testing and it was instantly on the pace, as well as reliable. Developed by Neil Oatley, the MP4/5 looked like the car to beat in the new season. While the Ferrari that season was a fast all-around car particularly in the hands of Nigel Mansell, it was also chronically unreliable due to its new semi-electronic gearbox shift, giving a further advantage to McLaren. The Honda-powered MP4/5 proved to have the outright pace over the rest of the field, with 15 pole positions, 13 of them by Senna which equalled his 1988 record in the MP4/4. At the Mexican Grand Prix, Senna scored his 34th career pole in the MP4/5, breaking the previous record of 33 held by the late Jim Clark that had stood since .