The interesting bit about the Ilmor relationship is that it stemmed from development of another Mercedes' branded motorsport superweapon. Ilmor was founded by

The interesting bit about the Ilmor relationship is that it stemmed from development of another Mercedes' branded motorsport superweapon. Ilmor was founded by 2 Cosworth engineers who disagreed with the development direction of the DFX CART engine, they started with funding from GM to design an Chevy-branded engine for CART which went on to win 6 straight Indy 500s. Despite their immense success, the Ilmor team wanted to design a one-off engine around a loophole that allowed much more regulatory freedom if the engine used pushrods instead of overhead cams. That loophole could theoretically allow an engine to make ~200hp more than the competition butGM was winning trophies hand over fist. They declined to fund the concept so the two companies parted ways. They still saw enormous potential in the pushrod concept and found willing partners in Roger Penske and Mercedes. Shortly thereafter the Mercedes 500l had been born, also known as Mercedosaurus Rex. It's the spiritual predecessor to this year's engine in that it was in a completely different league than its competition. If you're interested in motorsport history and engineering you should read this: http://8w.forix.com/penske-mercedes-pc23.html http://8w.forix.com/penske-mercedes-pc23.html It's nearly book length but it does a great job of explaining why the 500l deserves its place in motorsports legend.