i have a stock 04 GT 5spd and was wondering what gears should i put in, i also want to keep my gas milage somewhat.. and how much of a difference will i feel.

 

There are about 100 threads related to gears. Some will tell you 4.10s will hurt your mileage, some will tell you they won't. Some will tell you that 3.73s won't make a difference, some will tell you they will. If you want my opinion, get the 3.73s if your car is a daily driver. If you race it alot, and plan on getting more power upgrades, get 4.10s.

 

Yeah, it really comes down to future plans and how often you drive the car, and if you do a lot of highway driving or not.

 

okay thanks, ya it is a daily driver, since its the only car i own. but i also would like to get an increase in horse power and performance but without spending alot of money.

 

...I would go with the 3.73's!

 

It also sounds like you do not fully understand the effects of gearing changes.
The horsepower will not change. It will only allow you to get into the power curve quicker.

Most street driven Mustangs will see no difference in acceleration anyways since most street tires can not hook up even with stock gearing.
Take a car that spins the tires and add more gear? You will only benefit from more gear if you compliment it with a stick tire.

I have 3.73's in my 93 5L. Hate them 98% of the time. Every second I stand there pumping fuel into the tank and every kilometer I drive down the right lane on the highway.

The 2% of the time when I like them is on a glued drag strip. It's one of the few occassions when I can floor my car wide open in 1st gear.

 

3.73s will be your best bet. You're lucky the '04s had a higher 5th gear which helps a lot to keep the RPM down in 5th gear.