| « Jimmy Daywalt | Drivers / 1955 / Len Duncan | Ed Elisian » | |
| « 1954 | 1956 » |
| Full name: | Leonard Duncan |
| Nationality: | American |
| Date of Birth: | Tuesday, 25 July 1911 |
| Place of birth: | New York, New York, USA |
| Date of death: | Monday, 1 August 1988 |
| Age at death: | 77 years, 7 days |
| Debut: | 1954 Indianapolis 500 |
| Active years: | 1953 – 1956 (4) |
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| Rd | Date | Grand Prix | Constructor | Car | Grid | Race | Points | Champ. Points | Rank |
| 1 | 16 Jan | Argentina | |||||||
| 2 | 22 May | Monaco | |||||||
| 3 | 30 May | Indy 500 | Kurtis Kraft-Offenhauser | 500C | DNQ | 0 | 0 | NC | |
| Kurtis Kraft-Offenhauser | 4000 | DNQ | 0 | ||||||
| 4 | 5 Jun | Belgium | 0 | NC | |||||
| 5 | 19 Jun | Netherlands | 0 | NC | |||||
| 6 | 16 Jul | Great Britain | 0 | NC | |||||
| 7 | 11 Sep | Italy | 0 | NC |