John Duff![]()
John F. Duff
Birthplace: Kiukang, China
Born: January 17, 1895
Died: January 9, 1958
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| Track | Starts | DNS/DNQ | Wins | 2nds | 3rds | 4ths | 5ths | Best Finish | Poles | 
| Altoona | 1 | 0 | 0 | 0 | 1 | 0 | 0 | 0 | |
| Atlantic City | 0 | 1 | 0 | 0 | 0 | 0 | 0 | NS | 0 | 
| Indianapolis | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 9 | 0 | 
| Rockingham | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 13 | 0 | 
| Chassis | Starts | DNS/DNQ | Wins | 2nds | 3rds | 4ths | 5ths | Best Finish | Poles | 
| Miller | 3 | 1 | 0 | 0 | 1 | 0 | 0 | 0 | 
| Engine | Starts | DNS/DNQ | Wins | 2nds | 3rds | 4ths | 5ths | Best Finish | Poles | 
| Miller | 3 | 1 | 0 | 0 | 1 | 0 | 0 | 0 |