My '94 Chateau with 351, E4OD and 3:55 got 10 mpg consistently, no matter what I did with it, highway, city and towing. I did a little work on it a while back in response to a problem it was having and my city mileage has improved to a fairly consistent 12 and I got nearly 17 on the highway recently, but the road, the traffic and the weather were all perfect.

The injection system changed at some point in '95 or maybe '96. If it has a mass airflow sensor, it has the newer system and is capable of getting a little better mileage than my '94.

Also take into account how the van is equipped and the intended purpose. A bare bones E150 service van might do better, that a Clubwagon. A conversion van will be heavier and the aerodynamics will likely be worse (if that is possible) and of course a cargo van will depend on how much load you carry in it.

Your mileage will definitely vary. I would stay away from the V6.

Gene