With stock tires on my '96 convertible I normally got 30. If I really leaned on it I could get it down to 26-27. When I went to 235/75s, the best I could get was around 26ish adjusted, 24ish indicated.
As far as I've been able to gather on here when this conversation comes up, the '96 model year trucks seem to average a few MPGs better than the others. But then, they also seem to have more than their fair share of that damned ecu leaky capacitor issue, too.