Ok so apparently now they have the actual official details released
For the Ride
ALL-NEW FIRST-CLASS PERFORMANCE
At 2500cc, the world’s biggest motorcycle production engine is central to the Rocket 3 TFC’s new class-defining performance, delivering
165 FT-lbs (the world’s highest torque) and
179 horsepower, this is the most powerful Triumph to date. Adding to its unbeatable performance, the Rocket 3 TFC is also equipped with tailor-made, unique Arrow mufflers with carbon fiber end caps, for an unbelievable deep growling soundtrack