I don't think a 250 will get any milage with a 700R4, the torque curve is not what it needs to be at 1700 t0 1900 rpm. You will be better off with a 350 with a stock type cam. A 292 will do better then the 250 and should be about equal to the 350 in milage. Of course the 350 will out power both of them. Just look back at what the factory used and go from there.
