Um, If you have already made up your mind, just do it and see what happens.
BTW
you realize that that your 225 slanty might only gross 125hp right?
and at 500rpm idle has just enough power to idle in gear and not much more.
EDIT; and the powerloss will be proportional to the rpm. Actually, IIRC, proportional to the square of the rpm; meaning , when you double the rpm, it takes double double the power, so four times as much.