I cannot comment on the power that this, or that engine makes, people are optimistic with dyno results all the time, everywhere.
Industry-wide, there has been a reform couple years ago, where the manufacturers were suggested to have their engine outputs certified, which did result in changes to output in most cases.
This however, only has to do with manufacturer testing methodology.
But as far as the BHP, it's only specifying that it's brake horsepower, as opposed to wheel horsepower.
The brake horsepower, as a measurement unit, does not differ, in terms of watts by example, from a HP, by American definition.
Brake used to be the mechanical measurement device, which BTW could have removed ancilaries as well, such as a powersteering pump, alternator, or even water pump.