I didn't understand the Porsche 917 reference. Shelby said:
If I had built the car like a 917 Porsche, I would have been 10 years ahead of where we were.
The original 917's with the long tail were unstable disasters. It wasn't until John Wyers team hacked off the tail (like the Coupe) that the 917's became stable at speed and then began to dominate.
One positive thing to come of this: nice photos in the article!