PORSCHE RACING HISTORYKen Madren (USA)
1983 : Daytona 24 Hours - 3rd in class
6 February 1983 - Daytona 24 Hours - IMSA - International Motor Sport Association
| No. | Car | # | Class | Drivers | Entrant | Pos | Class | Grid | Notes |
| 24 | Porsche 935 JLP-2 | 009 00043 | GTP | M. L. Speer (USA)/Ken Madren (USA)/Ray Ratcliff (USA) | Pegasus III Racing (USA) | 4th | 3rd | 16th | 578 laps |
19 March 1983 - Sebring 12 Hours - IMSA - International Motor Sport Association
| No. | Car | # | Class | Drivers | Entrant | Pos | Class | Grid | Notes |
| 24 | Porsche 935 JLP-2 | 009 00043 | GTP | M. L. Speer (USA)/Ken Madren (USA)/Ray Ratcliff (USA) | Pegasus III Racing (USA) | 44th | 7th | 22nd | 145 laps - Engine |
10 April 1983 - Road Atlanta 500 km - IMSA - International Motor Sport Association
| No. | Car | # | Class | Drivers | Entrant | Pos | Class | Grid | Notes |
| 24 | Porsche 935 JLP-2 | 009 00043 | GTP | M. L. Speer (USA)/Ken Madren (USA) | Pegasus III Racing (USA) | 25th | 10th | 14th | 104 laps |
24 April 1983 - Riverside 6 Hours - IMSA - International Motor Sport Association
| No. | Car | # | Class | Drivers | Entrant | Pos | Class | Grid | Notes |
| 24 | Porsche 935 JLP-2 | 009 00043 | GTP | M. L. Speer (USA)/Ken Madren (USA) | Pegasus III Racing (USA) | 49th | 16th | 20th | 29 laps - DNF |
15 May 1983 - Charlotte 500 km - IMSA - International Motor Sport Association
| No. | Car | # | Class | Drivers | Entrant | Pos | Class | Grid | Notes |
| 24 | Porsche 935 JLP-2 | 009 00043 | GTP | M. L. Speer (USA)/Ken Madren (USA) | Pegasus III Racing (USA) | 4th | 4th | 9th | 134 laps |
19 June 1983 - Mid-Ohio 6 Hours - IMSA - International Motor Sport Association
| No. | Car | # | Class | Drivers | Entrant | Pos | Class | Grid | Notes |
| 24 | Porsche 935 JLP-2 | 009 00043 | GTP | M. L. Speer (USA)/Ken Madren (USA) | Pegasus III Racing (USA) | 9th | 4th | 18th | 193 laps |
14 August 1983 - Mosport 6 Hours - IMSA - International Motor Sport Association
| No. | Car | # | Class | Drivers | Entrant | Pos | Class | Grid | Notes |
| 24 | Porsche 935 JLP-2 | 009 00043 | GTP | M. L. Speer (USA)/Wayne Pickering (USA)/Ken Madren (USA) | Pegasus III Racing (USA) | 9th | 4th | 6th | 199 laps |
21 August 1983 - Road America 500 Miles - IMSA - International Motor Sport Association
| No. | Car | # | Class | Drivers | Entrant | Pos | Class | Grid | Notes |
| 24 | Porsche 935 JLP-2 | 009 00043 | GTP | Ken Madren (USA) | Pegasus III Racing (USA) | 48th | 13th | 21st | 5 laps - DNF |