PORSCHE RACING HISTORYBob Zulkowski (USA)
1978
18 March 1978 - Sebring 12 Hours - World Challenge for Endurance Drivers
| No. | Car | # | Class | Drivers | Entrant | Pos | Class | Grid | Notes |
| 45 | Porsche 911 | GTU | Gary Steele (USA)/Jim Gaeta (USA)/Bob Zulkowski (USA) | Vann's Auto Body | 63rd | 26th | 45th | 28 laps - Engine |
4 June 1978 - Trans-Am Westwood - Trans-Am
| No. | Car | # | Class | Drivers | Entrant | Pos | Class | Grid | Notes |
| 23 | Porsche 914/6 | 473 29 24107 | TA-I | Bob Zulkowski (USA) | Metal Craft Racing (USA) | 21st | 14th | 19th | 19 laps - CV Joint |
11 June 1978 - Trans-Am Portland - Trans-Am
| No. | Car | # | Class | Drivers | Entrant | Pos | Class | Grid | Notes |
| 23 | Porsche 914/6 | 473 29 24107 | TA-I | Bob Zulkowski (USA) | Metal Craft Racing (USA) | 32nd | 21st | 32nd | 5 laps - Engine |
8 October 1978 - Trans-Am Laguna Seca - Trans-Am
| No. | Car | # | Class | Drivers | Entrant | Pos | Class | Grid | Notes |
| 23 | Porsche 914/6 | 473 29 24107 | TA-I | Bob Zulkowski (USA) | Metal Craft Racing (USA) | 31st | 19th | 24th | 33 laps - Turbo Failure |