In a limited slip:
An explorer rear, 3.73-4.10 gears.
A ranger, you can bet 3.45-4.56s
An Aerostar, you can get 3.55s only
I think in a mustang, you can go as numerically low as 3.08
Check this site: http://www.therangerstation.com/tech_library/Axles.html
