Ok, unlocked again.
Interesting to follow your discussion. I am absolutely sure too, that there's a connection between the puzzle car and the Targa Florio car, you've found.
1972 is correct, Porsche-based is correct, and Alfio Nicolosi was envolved.
But: It is designated to the company, which built the car. It haven't used an engine for competiton class 1601-2000ccm and it wasn't based on a 910