There is no engine comparrison chart that I know of. If there is my first reaction is it is bogus.
When talking about engines, and testing power there are SO many different variables when testing that power that is leaves room to scue or "play" with the numbers.
You will see that some of the "best" engine manufacturers (by reputation) do not put a BHP rating on their engines do to the many different ways of rating the horse power. Some exapmles to help put it together for your are Company A dyno's their engine at the crank, while Company B dyno's their engine at the clutchbell gear. Company A is in Colorado and Dyno's at 5000+ ft and Company B Dyno's their engine at sea level.
I use bhp ratings as a general guestiment, not to say that some companies methods are not dead on as some are true blue. Also what percentage of nitro fuel and types of oils used come into play, as well as ambient temp, and humidity.