PORSCHE RACING HISTORYPreston Henn (USA)
1981
1 February 1981 - Daytona 24 Hours - World Championship for Drivers and Makes
| No. | Car | # | Class | Drivers | Entrant | Pos | Class | Grid | Notes |
| 09 | Porsche 935 K3 | 930 890 0021 | GTX | Preston Henn (USA)/Bob Bondurant (USA) | Thunderbird Swap Shops (USA) | 64th | 23rd | 15th | 30 laps - Engine |
21 March 1981 - Sebring 12 Hours - World Championship for Drivers and Makes
| No. | Car | # | Class | Drivers | Entrant | Pos | Class | Grid | Notes |
| 09 | Porsche 935 K3 | 930 890 0021 | GTX | Preston Henn (USA)/John Gunn (USA)/Gary Belcher (USA) | T-Bird Swap Shop (USA) | 48th | 15th | 18th | 107 laps - DNF |
26 April 1981 - Riverside 6 Hours - World Championship for Drivers and Makes
| No. | Car | # | Class | Drivers | Entrant | Pos | Class | Grid | Notes |
| 08 | Porsche 935 K3 | 000 0009 | GTX | Preston Henn (USA)/Marty Hinze (USA)/Gary Belcher (USA) | Preston Henn (USA) | 45th | 16th | 40th | 33 laps - DNF |
26 April 1981 - Riverside 6 Hours - World Championship for Drivers and Makes
| No. | Car | # | Class | Drivers | Entrant | Pos | Class | Grid | Notes |
| 09 | Porsche 935 K3 | 930 890 0021 | GTX | Gary Belcher (USA)/Preston Henn (USA)/Marty Hinze (USA) | Preston Henn (USA) | 58th | 20th | 15th | 5 laps - DNF |
10 May 1981 - Silverstone 6 Hours - World Championship for Drivers and Makes
| No. | Car | # | Class | Drivers | Entrant | Pos | Class | Grid | Notes |
| 27 | Porsche 935 K3 | 000 0009 | Gr.5 | Adrian Yates-Smith (GB)/Preston Henn (USA) | Preston Henn (USA) | DNF | 19th | 143 laps - Accident |
14 June 1981 - Le Mans 24 Hours - World Championship for Drivers and Makes
| No. | Car | # | Class | Drivers | Entrant | Pos | Class | Grid | Notes |
| 41 | Porsche 935 K3 | 000 0009 | IMSA GTX | Preston Henn (USA)/Michael Chandler (USA)/Marcel Mignot (F) | Preston B. Henn (USA) | DNF | 17th | 45 laps - Crankshaft Pulley |
12 July 1981 - Watkins Glen 6 Hours - World Championship for Drivers and Makes
| No. | Car | # | Class | Drivers | Entrant | Pos | Class | Grid | Notes |
| 22 | Porsche 935 K3 | 930 770 0960 | Gr.5 | Marty Hinze (USA)/Dale Whittington (USA)/Preston Henn (USA) | Marty Hinze Racing (USA) | 5th | 5th | 15th | 157 laps |
16 August 1981 - Mosport 6 Hours - World Championship for Drivers and Makes
| No. | Car | # | Class | Drivers | Entrant | Pos | Class | Grid | Notes |
| 09 | Porsche 935 K3 | 000 0009 | GTX | Preston Henn (USA)/Edgar Dören (D) | Preston Henn (USA) | 4th | 4th | 17th | 219 laps |
29 November 1981 - Daytona Finale 250 Miles - IMSA - International Motor Sport Association
| No. | Car | # | Class | Drivers | Entrant | Pos | Class | Grid | Notes |
| 09 | Porsche 935 K3 | 000 0009 | GTX | Preston Henn (USA)/Bonnie Henn (USA) | Preston Henn (USA) | 49th | 15th | 28th | 31 laps |