I have a similar story, only it took place on the N1 North, just North of Pretoria and involved an Audi 100 5E automatic and a supposedly fast XR6 Cortina, we had a rolling start at 100km/h, I was in the Audi and at the start, I pulled away as the automatic was on a sweet spot on 100 km/h, in the end we ran together at 185 km/h, the guy in the 3 litter ford could not believe that he could not beat a 2.2 automatic . At the end of the race the Ford was running very hot and the Audi was still fine.