I'm rather curious about the story of this car. I can't seem to find too many details about this car apart from a single paragraph on Wikipedia in the disappointingly short review of the 1971 24 Hours of Le Mans. I am aware that the car went through some significant aero and engine changes compared to even the '71 512M, but the details I was able to find are extremely sketchy. So because of this I turn to the knowledge repository that is TNF to seek more information about this project.
Also, if the car still exists, does it still reside with Penske or is it in private hands nowadays?