Sorry, things still don't add up for me. Essentially the same engine as 296GTB (650HP), plus 20% more boost, how does it make 900HP? If Ferrari indeed has figured out the next quantum leap in ICE technology, everyone needs to jump on this asap. Can you imagine a 1000HP+ 4.0L McLaren ICE only car as their next super series car without all the electrical weight and complexities? It will sell like hot cakes.
My best GUESS that comes to my mind is Ferrari is really dancing on the edge and temporarily over boosting the engine and back off before too much knocking kills the engine. Being a 1/799 hypercar that won't be driven, reliability is not a huge concern. Maybe the ICE power only last a short while. This aligns with their language about the feature that learns the track and pick the spots for peak power delivery. Or they rely more on battery power than they care to admit. With the V6, the car feels more like an EV with a motor strapped on it than the other way around. I would love to be wrong here.