PORSCHE RACING HISTORYDieter Oest (USA)
1973
4 February 1973 - Daytona 24 Hours - World Championship for Makes
| No. | Car | # | Class | Drivers | Entrant | Pos | Class | Grid | Notes |
| 89 | Porsche 911 S | GT+2.0 | Mike Tillson (USA)/Al Holbert (USA)/Dieter Oest (USA) | Holbert Porsche (USA) | DNF | 42nd | 213 laps |
24 March 1973 - Sebring 12 Hours - Non Championship Race
| No. | Car | # | Class | Drivers | Entrant | Pos | Class | Grid | Notes |
| 92 | Porsche 911 S | GTU | Dieter Oest (USA)/Don Heth (USA)/David Olimpi (USA) | Holbert's Porsche-Audi (USA) | 25th | 9th | 70th | 174 laps |