This newly available English language edition is identical to the German one. Of course that includes the high quality paper, production values, and the comprehensive text by Walter Naher. As a newly-minted engineer, Naher went to work for Hans Mezger in Porsche's Testing Department in 1969, just as the 917 was coming online. (Mezger designed the 917's engine.) Naher went on to a long career at Porsche and Sauber. But the 917 made the earliest and deepest impressions on him. This book was a labor-of-love retirement project for him.
The book is dual-purpose: a high-quality illustrated "coffee table book" and an exhaustive history of the 917. With the English edition, I can instantly understand Naher without resorting to a German-English dictionary. A Porsche expert told me this is the book on the 917. Having seen many, I agree. The chapters on, and pictures of, aerodynamic development (including blind alleys) are fascinating.
Regular readers of this blog know that I have a case of obsessive-compulsive disorder with the 917, and yes, the English edition of this book cleared up my confusion about Wyer-Gulf chassis numbers 004/017 and 026/031.
There is a madcap consistency to 004/017. 004 was not raced by Wyer as 004 (it was raced by Porsche themselves in 1969). Porsche rebuilt the car and renumbered it 017 before sending it to Wyer for 1970. Nevertheless, John Horsman backnumbered it to 004. This was his usual practice for cars that had been raced by Wyer and then sent back to Porsche for rebuild. His purpose was to maintain chassis number and history across all components of a car. So 004 is consistent with Horsman's practice even though it was never raced as 004 by Wyer. (Porsche practice with the 917 was to consider a rebuilt car, or a new spare frame used to rebuild a car as a new car.)
026/031 still gives me a headache, even after the Naher sort-out. 026 was built in 1969 as a spare frame (the first number after the 25 homologation cars). In 1970, it was used to build car 026 for Wyer. That car was crashed at LeMans and sent back to Porsche for rebuild using frame 031. Horsman continued to consider the car as 026. It was returned to Porsche in September 1971 and rebuilt by the factory over the winter as spyder 026 and sold to a customer for Interseries racing. (The Interseries was Europe's version of the Can-Am.) In 1973 the spyder was sold to Vasek Polak in Los Angeles, who reconverted it to a coupe in Wyer-Gulf colors, still numbered 026. Repaired frame 026 was put into Porsche's spares stock as 031 (a switcheroo, by Porsche's standards). It was used to build a new spyder Interseries customer car, 031.
The confusion over some chassis numbers would be of little importance if the 917, particularly the cars used by professional teams in FIA racing, had not become so iconic, and valuable. But the confusion, and the reasons for it, demonstrates how sketchy the provenance of a race car can be. In fact, Porsche and the pro teams it supported kept better records than most.