Just a side note: NEVER listen to other people's "estimates" of how far a CPU will overclock. Nobody will ever be able to predict overclockability, and false hopes will just frustrate you. Hands on testing is the only way to determine what a chip will do, with wildly different variables.
That being said, go to some of the CPU databases, such as at Overclockers.com, and see what other people have been able to do (though some lie or don't get the concept) with chips with the same codes.