[FONT=Arial,Helvetica,Geneva,Swiss,SunSans-Regular]What gear would be best for my car?[/FONT][FONT=Arial,Helvetica,Geneva,Swiss,SunSans-Regular]
This is one of the most commonly asked questions we get. There are always concerns over gas mileage, streetability and highway cruising. The decision between 3.55, 3.73 or 4.10 gears is usually a monumental one for people but shouldn't be. [/FONT]
[FONT=Arial,Helvetica,Geneva,Swiss,SunSans-Regular]The best all around performance gear is the 3.73. Gas mileage isn't really affected, in fact we've had customers report better gas mileage when going to this gear from a 2.73 or 3.08. The 3.73 gives an excellent increase in acceleration and top speed isn't decreased because you are able to wind out overdrive further. With a 3.73 your rpm in 5th gear at 60 mph will only be 2005, not at all what you would call "too high". As we said, your top speed will not decrease when putting lower (numerically higher) gears in a car with overdrive. You will simply wind out 5th gear further than you could with the higher gears (numerically lower). [/FONT]
[FONT=Arial,Helvetica,Geneva,Swiss,SunSans-Regular]The 3.55 is also a good choice for a daily driver but does not offer the acceleration potential of a 3.73. With a 3.55 your rpm in 5th gear at 60 mph should be right around 1908. To sum it up, for a 5 speed car we feel the 3.73 is the best all around performance choice but either gear will make your car feel 1000 lbs. lighter and a whole lot quicker. [/FONT]
[FONT=Arial,Helvetica,Geneva,Swiss,SunSans-Regular]Now, if your pony car has the 4 speed AOD it's a whole different ball game. The AOD is not the most responsive transmission Ford has ever made and it needs all the help it can get. For the AOD, 3.55's are simply not enough. 3.73's are a good choice for automatic cars and again, they don't hurt gas mileage very much and the car remains as streetable as it was from the factory, only it accelerates much better. 4.10's are also a good choice for automatic cars, and we prefer them. A 4.10 may sound extremely steep, but because the AOD's 1st gear is so high (numerically low) and 4th gear (overdrive) is steeper than the T-5 it's a very good choice for the driver interested in making their car perform better. [/FONT]
[FONT=Arial,Helvetica,Geneva,Swiss,SunSans-Regular]As for the 4.10 in a stick car, we really don't recommend them for stock engines, but if you've had other work done like an intake and heads they're an excellent choice. At 60 mph in 5th gear 4.10's will bring cruising rpm up to 2204. 2204 rpm still isn't bad on the expressway but in the city you'll be doing a lot of shifting, but if that's not a problem, 4.10's offer a hellatious launch and rate of acceleration.[/FONT]
I want to change the gears in the back of my 99 GT, but i'm not sure what size gears to go with, Any suggestions/tips are welcome ! 
