figure what gears you have
lift the rear of the car and support it. spin the rear wheels exactly one full turn and count the number of times the drive shaft spins. if your rear wheels turn one full time and the drive shaft turns 3 3/4 turns ratio would be 3.73. if your rear wheels turn once and the shaft turns 4 1/8 turns, you have 4.10 etc. thats an easy way without removing anything.
2000 V6 .030 over comp cam, k&n cai,
underdrive pulley set. mac headers, mac h pipe flowmaster catback, aluminum ford racing drive shaft ford racing 4.10 posi. And a 05 V6 for every day use.