I'm Here
 

Well I am a new member and I Have a 2004 mustang GT 5spd. with flowmaster40's,K&N air filter with the air scilencer removed and my 4.10 gears will be here this week. What do ya think? and what should my 1/4 mile time and speed be befor and after the 4.10s.

Welcome to the site! :D

I can't make any predictions on your time, especially with a 5 spd. You're definitely in the 13's with good driving, but that's the closest guess I can give. Your best bet is to just run it.

Sweet ride, but is that a lift kit on there?

no lift kit
 

How do you like the 3.90 gears,from stock? How much difference did they make?

Im still waiting to do mine. Ive got to order my sct xcalibrator first.
Steeda offers an insert so you dont have to recal your gears, but they arent available for 3.90s. Its like 30 bucks for it too.

Welcome, car looks great, and about the Steeda insert, if you are talking about the speedo-gear, then they wont work on our cars. Our trannys have electrical speedometers, or something like that, that wont let us just use a new speedo gear. Our cars have to have a chip, programmer, or speedcal to fix it. I just used a speedcal and its dead on.

Diablo
 

Yea I can fix the speedo with it. I just got to find a good place here in Rochester ny to put the geers in.