After backers Iso and Marlboro left Frank Williams before the 1974 season, his team continued to use Iso-Marlboro car from 1973 in slightly revised specification. The car was renamed the Iso–Marlboro FW, and Arturo Merzario who left Ferrari, moved to Williams. Experienced Italian was able to get top-6 finishes at Kyalami and Monza, and Frank Williams team finished the season in 10th position ahead of Surtees, Lola and eight other F1 teams. The second Iso-Marlboro car was entered since the South African Grand Prix driven by various drivers – Dane Tom Belso, Dutch Gijs van Lennep, French Jean-Pierre Jabouiille and Jacques Laffite. Belso, Scandinavian Touring Car Champion in 1969 and former Formula 2 racer, tried four times to qualify for Williams, but was only successful in South Africa and Sweden. In South Africa, the clutch on Belso’s FW failed on the first lap of the race. In Sweden, he finished his only complete Grand Prix, in eighth place.
| Season | Series | Event |
| 1974 | F1WC | Swedish GP |
| Driver | No. | Entrant |
| Tom Belso | 21 | Frank Williams Racing Cars |
| Scale | Manufacturer | Collection |
| 1:43 | Spark | |
| Cat. No. | Quality | Rarity |
| S4040 | 
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