For one thing I dont think it is offered any more, (only BA and China Yunnan ever bought them, although QF took a few of the BA birds on lease for a long while as well) and second, rolls-powered 767s are not certified for the AV partners winglets which their 763s do have.
Also the RB211-powered 767s dont have the same range as the GE/PW birds. Fuel burn is comparable i hear, but range and performance not as good. Not sure of the exact figures, but im sure one of our sadder members can reel off the exact figures from memory!
[Edited 2010-12-02 04:58:16]
What do you mean you dont have any bourbon? Do you know how far it is to Houston? What kind of airline is this???