The site above is likely an old site created before the 1999 24 Hours of Le Mans race. Its all over and done with (considering that it is now 2001) and the R391 specifications are listed throughout the web. If you cannot find much information, it is because the R391 was not that popular, especially with its short life on the track (Nissan pulled out of Le Mans before 2000 due to budget cuts). If you are wondering why the engineers at Nissan decided to use an all-new naturally aspirated 5.0L V8, instead of the proven TWR 3.5L V8 twin turbo, it was because they decided that a free-flowing high torque motor with a broad powerband would be less strenuous to the drivers who need to concentrate on the track, rather than boost-lag, and other turbo related drawbacks. Even with all that effort, the R391 was left behind, and afterwards left in the dark... one can only hope that Nissan will rejoin the pack at Le Mans in the future and perhaps one day, like Mazda, be victorious, carrying the flag of the rising sun.