It is more than likely a 790 if it is in fact from an 05. thats not really a problem though. you should pull the plugs and look at them and get an endoscope and look inside to see the cylinder walls and check the valve clearances. to make sure its a healthy motor. I think its an endoscope any way there is a small led on the end of a fiberoptic tube that you can slide in through the sparkplug hole and have a look see.

I have no faith in human perfectability. I think that human exertion will have no appreciable effect upon humanity. Man is now only more active - not more happy - nor more wise, than he was 6000 years ago. Edgar Allan Poe