I must say this discussion would look much more pleasant to me if you could refrain from pontificating against other knowledgeable people (and you did so at your own expense with Martin in the discussion over GTA/SAs) based on your admiration for the late Tabucchi.
Not only was Tabucchi not so much recognized for the accuracy of his research (see 1990s La Manovella about his 2-volumes "Alfa Romeo di produzione and his invention of a "forgotten" Alfa which was, in the end, an old Darracq design updated), but you seem quite selective in your reading.
I must correct you about "Busso himself has never mentioned (not even in autobiography)".
And, if it's not specific enough:
While Collins' and McDonough's book on 33s is at least as much packed with errors as Tabucchi's, they remark on page 18:
I reckon that further in the book, they make confusing statements about the engine's origin, and BTW report having seen "castings for a 2-litre V8 produced during the 1950s, again for a stillborn passenger/GT car".
I have myself researched the Arese archives for an history of the Alfa factory in the 40s and 50s, and didn't came across any plan for such a car. That doesn't rule out that the castings do exist, but I'm in doubt which project they can have been related to.
I am sorry if my comments sounds like papal edicts to you. It is due to my modest English, not my intention. However, I have to admit that our points of view (and sources) are profoundly different.