There should be a sticker on the valve cover with the hp and rated rpm. If not try to find the ESN and call Cummins.
EDIT: Looks like 275hp.
http://www.winnebagoind.com/products/previous-models/2000/pdfs/winnebago/00-Journey-bro.pdf
MrWizard wrote:
As said the rating varies with the application
The injectors used and the amount of turbo boost
My 1995 is rated at 230hp,
Boost isn't really a hp indicator, too many variables such as cam, head, timing, and turbo effect boost for the same hp. I make about 140rwhp over stock with less boost and lower EGTs than stock.