I may have stumbled across a leak as to what engine will be in the 2011 mustang. All I will say is that this person works for an aftermarket company that makes performance parts for V8 engines. He was talking about a product for another car and then referred to the 2011 mustang parts being developed now and ahead in progress of the other cars part because he received the specs he needed about the 2011 mustang engine prior to the other cars.
I'll do him one better. I found out, through a pretty good source, that a company that makes motor mounts for ford is at the very least testing 5.0L motor mounts for the Mustang.
I just heard back from him and he is also saying the cad designs he received for the 2011 Mustang is for the 5.0L V8. I was making sure when he first told me that he didnt mistakenly put 2011 instead of 2010. He wrote me back and confirmed that is it the 2011 and it is the 5.0L V8.
We now have two different aftermarket leaks saying the 5.0L is coming so hopefully it is true.
In the line of credible people dealers are usually the last. That is of course until it is sitting on their lot and even then they will sometimes be wrong on the specs of a vehicle. Dealers won't know anything until the order banks open up with the new engine listed and again only the dealers who take the time to look into it will know anything.
PS
In 2005 I had a dealer try to get me to put down money on the "2006 Boss 302" that they promised was about to come out.