PORSCHE RACING HISTORYJack Refenning (USA)
1978 : Daytona 24 Hours - 3rd in class
5 February 1978 - Daytona 24 Hours - World Championship for Makes
| No. | Car | # | Class | Drivers | Entrant | Pos | Class | Grid | Notes |
| 08 | Porsche 911 S | 911 030 1263 | GTU | Terry Wolters (USA)/Jack Refenning (USA)/Ray Mummery (USA) | Terry Wolters | 14th | 3rd | 55th | 584 laps |
18 March 1978 - Sebring 12 Hours - World Challenge for Endurance Drivers
| No. | Car | # | Class | Drivers | Entrant | Pos | Class | Grid | Notes |
| 27 | Porsche 911 S | GTU | Ray Mummery (USA)/Jack Refenning (USA)/Tom Sheehy (USA) | Miami Auto Racing | 52nd | 23rd | 50th | 70 laps - Clutch |
2 April 1978 - Talladega 6 Hours - World Challenge for Endurance Drivers
| No. | Car | # | Class | Drivers | Entrant | Pos | Class | Grid | Notes |
| 27 | Porsche 911 S | GTU | Ray Mummery (USA)/Jack Refenning (USA)/Tom Sheehy (USA) | Ray Mummery | 15th | 5th | 26th | 142 laps |
27 August 1978 - Mid Ohio 250 Miles - IMSA - International Motor Sport Association
| No. | Car | # | Class | Drivers | Entrant | Pos | Class | Grid | Notes |
| 27 | Porsche 911 S | GTU | Jack Refenning (USA)/John Gunn (USA) | 33rd | 10th | 34th | 73 laps |