http://www.twinturbov8.com/dynostuff.htm

have a look at this article.

I cant vouch for its acurracy obvioiusly, but from the way the author has written the article it doesnt seem like a "bragging rights" article

Just thought it'd be interesting and useful (if accurate) to put to rest all those arguments as to whether USA dynos really read more HP than ours and what (as a general rule of thumb) we lose through our drivetrains