To help with highway mileage the 2.73 gears from a Crown Vic or Marquis might help. Check the axle code, I think the Town cars were 3.55.
However if most of your driving is in town, an axle change might not help, and could even hurt mileage.
I hope soon to get into a Crown Vic or Marquis for highway trips, and you might consider trading into one of them--some owners claim 30 mpg or more with the 2.73 gears.
Ray Mac
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