Just spit wadding, unless something in the way of a miracle happens, government policy has been and will continue to be based on politically driven science and the accompanying mpg mandate will pretty much make V8's an extinct species except for high dollar variants that will certainly come with gas-guzzler taxes. Smaller power plants will rule the day and the 3.7L we drive today could represent the upper end of the displacement ladder. "F" may be banking on the data derived from this little experiment to either improve on an existing platform or assist in the development of something entirely new that will be leading the way in the new age of smaller displacement powerplants. As to the question of 1000 HP from a 3.7L, yes it's possible, but only if you spend a small fortune to arrive at an engine that will be buzzy and likely short-lived or you can spend a large fortune and eliminate the NVH and arrive at a reliable power plant, but other than the benefit of research the question would remain, why?
You wont see V8's disappearing ANY TIME SOON, as there is Just too much Coin to be made!....Even with the new for '16 CAFE Ratings going into effect Companies like Ford can keep the Fleet average way down by way of coming up with engines just Like the 1.0 L TiVCT Turbo that will be going into the Fiestas, Base Focuses ect......You will NEVER Live to see the Death of the V8 Engine, especially a Ford variant because of how clean DOHC engines that they have Run compared to GM's V8's that although now using DI, they just cant run as Clean or efficiant as Fords TiVCT V8's......