I want to add 3.73 gears, what do i need?
Usually you have to buy a ring and pinion set, lets say from Richmond, or Randy's Ring and Pinion. You would also have to buy an install kit which should come with shims, pinion seal, inner and outer pinion bearings, and carrier bearings. The gears and the install kit will prob run you about 300, and you looking at about 5 hours install time with a professional shop, depending on their labor rate (around here its around 100 bucks and hour) itll cost you around 800 for the total job. This is TOTALLY worth it. Gears are one of the biggest mods you can do for a street car and ther 4.6 in your mustang with respond great. (im not even a ford guy)