PORSCHE RACING HISTORYJack Refenning (USA)
1979 : Sebring 12 Hours - 3rd in class
4 February 1979 - Daytona 24 Hours - World Championship for Makes
| No. | Car | # | Class | Drivers | Entrant | Pos | Class | Grid | Notes |
| 33 | Porsche 911 | GTU | Peter Welter (USA)/Richard Aten (USA)/Jack Refenning (USA) | Peter Welter | 13th | 5th | 55th | 550 laps |
17 March 1979 - Sebring 12 Hours - World Challenge for Endurance Drivers
| No. | Car | # | Class | Drivers | Entrant | Pos | Class | Grid | Notes |
| 33 | Porsche 911 | GTU | Peter Welter (USA)/Richard Aten (USA)/Jack Refenning (USA) | Peter Welter | 16th | 3rd | 49th | 198 laps |