Using this lightened 701/1 car Amon qualified third for the 1970 Belgian Grand Prix, where Stewart yet again took pole position in Tyrrell's 701/2. Amon's team mate Siffert qualified in tenth position and Peterson, again driving the Antique Automobiles car, went one place better and qualified in ninth. In the race Stewart retired on lap 14 after his engine failed, and Peterson eventually crossed the line eight laps down on the winners and not classified. For the second race in a row Siffert was forced to stop as a consequence of fuel issues, but again he had completed sufficient laps to be a classified finisher, this time in seventh place. Amon, though, spent the majority of the race in second place and chasing hard behind Pedro Rodríguez's BRM. He was eventually beaten to the victory by the Mexican by only 1.1 seconds. Some controversy surrounded this win, however, and both Amon and Robin Herd have since alleged that Rodríguez's car was equipped with an illegally large engine for that race. This was later refuted by BRM historian Doug Nye, who could find no evidence either that a switch had been made, nor that at that point BRM had sufficient resources to be able to construct such an engine.