If you could pick up an AOD, say, from a wrecking yard cheap enough, and didn't want to rebuild it first, $800 may be reasonable enough for the AOD swap. I would say that a 3-5 mpg increase on the highway is plenty acheivable with the AOD.
On the way to L.A. from Sacramento (roughly 650 mile trip), every time the rest of the caravan wanted to stop for gas I always had at least 1/4 tank more than them ... and I, by far, had the most radical engine in the group, and probably the steepest gears in back (3.0 open rear) of any.
Around town the overdrive helps some, but not all that much. I spend most of my time between 2nd and 3rd gear, and only occassionaly shift it into overdrive.
If you must sell the car, you must sell it ... but you'll always, always regret it.
On the way to L.A. from Sacramento (roughly 650 mile trip), every time the rest of the caravan wanted to stop for gas I always had at least 1/4 tank more than them ... and I, by far, had the most radical engine in the group, and probably the steepest gears in back (3.0 open rear) of any.
Around town the overdrive helps some, but not all that much. I spend most of my time between 2nd and 3rd gear, and only occassionaly shift it into overdrive.
If you must sell the car, you must sell it ... but you'll always, always regret it.