For the 1973 season Frank Williams Racing Cars team managed to get backing from cigarette giant Marlboro and Italian sports car manufacturer Iso Autoveicoli S.p.A. The Politoys FX3 from 1972 was reworked as the Iso–Marlboro FX3B and a second car was built. Two new drivers were signed, New Zealand’s Howden Ganley and Italy’s Nanni Galli. The FX3B was used for the first three races of the 1973 season. Then new car was designated as Iso-Marlboro IR, or Iso IR01. It was designed by John Clarke, featured aluminum monococque with Ford Cosworth DFV engine as a fully stressed member. The new IR appeared at the fourth race of the 1973 season and gained 2 points at the end of season. Ganley, who raced for Williams the whole season, took 6th place in the penultimate Grand Prix in Canada. Galli was injured testing a sports car and replaced after Monaco Grand Prix on race-by race basis. One of his replacements, Dutch Gijs van Lennep drove IR to sixth place in his home Grand Prix at Zandvoort. French Henri Pescarolo drove IR01 in French GP (retirement) and German GPs (10th). The IR continued to race two more seasons – in 1974 and 1975 – but in slightly modified and renamed form – Iso-Marlboro FW in 1974 and Williams FW in 1975.
| Season | Series | Event |
| 1973 | F1WC | French GP |
| Driver | No. | Entrant |
| Henri Pescarolo | 26 | Frank Williams Racing Cars |
| Scale | Manufacturer | Collection |
| 1:43 | Spark | |
| Cat. No. | Quality | Rarity |
| S7571 | 
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