Changing 5th gear in TC T5
I was wondering if it is possible to put a higher (?) 5th gear in an 88 TC T5 to lower my revs on the freeway and increase my gas mileage, while retaining stock first through fourth gears (btw, this is behind a 5.0)...? I also might put a mustang spec T5 in the car with 4.10's in the rear and want to do the same, but either trans...can it be done and how big of a job would this be? How much would it cost to have a shop do it?