Frederick the Great

Thanks for the help. I think I will go with 4.10's because I don't plan on supercharging (for the next five years anyway).haha

TRMN8TR

don't wast your time with 3:73's, been there and really didn't notice that big of a difference. go with 4:10's i think it's the absolute best gear in our cars

failurze_art

While you are in there, might as well throw in a good posi trac unit!

jerjan

Big diferenceon minefrom 3.31s to 3.73s. If I was staying normally aspirated I would have gone to 4.10s or 4.30s. I am supercharging this year, so I chose the 3.73s. If your gonna stay normally aspirated then by all means go with lower gears.

dirtydeedsinc

All those with 4.10s, how bad did gas mileage suffer on the highway? I'm running an auto with 3.31 and most of my driving is on the highway since it's right at 500 miles each way to work. How did it affect your top end too? I like being able to bury the needle ot at least get it to the last mark on the speedo.

I'm on the fence too on the gears. I had decided on 3.73 until I read this post. One of these days I'll learn to stop reading.

Jays Mustang

3:73 are a nice all around gear. Good for straight line drag and good for a trip on a highway. 3:90's a little better if racing alot but still streetable. 4:10's if mostly racing and not much highway use. 4:56's if strickly racing.

mustangman02232

you do realize there are people on here who say that they hated 4.30s and wish they went with 4.56s for a DD?

theses arent the pushrod cars of the 60s/70s with a 1;1 final drive, these are SOHC cars wtih a .62 or a .75 5th gear which is tall, a set of 4.10s in an auto or 4.30s in a 5 speed will allow the motor to rev like it needs to, peak horsepower is at 5700 rpm and peak torque is 4500 rpm, 3.73s will just not the motor rev up as quickly to get into the power band, some people will say 3.73s with FI, well, cant really say on things like KBs and etc, but on centris, as long as you have some better then stock rubber and some small suspention work they kick ***

2k05gt

I lost 1-2 MPG in the Highway and picked up 1mpg in the city.
unless you are planning on Trapping at over 120 mph in 4th 4.10 are fine
There is no way you will reach the TOP END with the N/A Car, the S197 is restricted by drag at about 150. I hit 142 MPH with 4,10's and still had room to go.

CLICK THE LINK ON MY SIG CALLED MUSTANG CALCULATOR
this will calculate the gear ratio for the S197 RPM / MPH ect.. Great Tool
this should help you decide what gear to get by seeing the shift points on a graph

[IMG]local://upfiles/25187/368922836012423DAACFF54E4070E228.jpg[/IMG]

Thunderbutt

Hey Everyone,
I have determined by the gear calculator if I go with 4.10's I will be turning 2700rpm at 80mph compared to my current 2200rpm.
My question to all with 4.10's ******DO YOU GET EXCESSIVE NOISE FROM YOUR TAIL PIPES AT THIS RPM LEVEL?******
At my current 2200rpm it is very quiet.

06Redfire3V

too be honest i think that around 2500-2600 rpms is when it gets more noticble as loudness goes