PORSCHE RACING HISTORYRobert Overby (USA)
1979 : Daytona 24 Hours - 3rd in class
4 February 1979 - Daytona 24 Hours - World Championship for Makes
| No. | Car | # | Class | Drivers | Entrant | Pos | Class | Grid | Notes |
| 98 | Porsche 911 Carrera RSR | GTO | Lance Van Every (USA)/Ash Tisdelle (USA)/Robert Overby (USA) | Van Every Racing (USA) | 9th | 3rd | 30th | 579 laps |
17 March 1979 - Sebring 12 Hours - World Challenge for Endurance Drivers
| No. | Car | # | Class | Drivers | Entrant | Pos | Class | Grid | Notes |
| 01 | Porsche 911 | GTU | Dave White (USA)/Robert Overby (USA) | Roehrig Racing | 29th | 8th | 31st | 147 laps |
4 July 1979 - Daytona Paul Revere 250 Miles - IMSA - International Motor Sport Association
| No. | Car | # | Class | Drivers | Entrant | Pos | Class | Grid | Notes |
| 88 | Porsche 911 S | GTU | Joseph Hamilton (USA)/Robert Overby (USA) | Hamilton House Racing | 39th | 14th | 35th | 18 laps |