Thanks for the welcome Enzo250GTO.
Before the Gallardo was signed off, Ferrari did consider using the current Maserati 4200 block for their next 360 replacement. After all Ferrari developed that engine when they bought 100% of Maserati and decided to start marketing in the US again. They had to have a normally aspirated engine, because the turbo engine would not pass the emission regulations of the US, hence the current 4.2 litre.
But based on current rumour Ferrari will not use that block but will develop a new engine altogether. They have not decided whether it will be a V8 or even a V10. Now that Lambo, Audi and BMW will have V10s in their cars, the decision has been forced on to Ferrari. They have to maintain their engine technology superiority and waht better way than to have a V10 as well. Besides a V10 would be the natural step up.
Ferrari does not have experience in road going V10 but their F1 V10 experience is just about the best, as good as BMW's, which reputedly have the "best" engine. So why not exploit the F1 success and trasfer that to the best selling model. A 500bhp V10 weighing 1350kg would be truly awesome.