Introduced at the 1973 Spanish Grand Prix, the Iso–Marlboro IR was driven by eight different drivers during the rest of the 1973 season. Ganley was the only regular driver and he scored a point with the car at the Canadian Grand Prix towards the end of the season. Of the other drivers; Galli, Pescarolo, Tom Belsø, Graham McRae, Gijs van Lennep, Tim Schenken and Jacky Ickx, only van Lennep was able to score a point, at his home race in the Netherlands.