04blkstang

These are in the 2000 Cobra R, so i guess it would be good and anything is better than stock but are they worth it. I dont wanna lose gas mileage too much and i heard 4.10's are gas hogs so 3.73 or 3.90 i see but i was wondering about the 3.55 in the cobra R??? good or bad?

01yellowgt

There is a guy in town that has 3.55's and he sounded like he liked them em but is going a 3.90's

with 4:10's in with all city driving I got 17mpg, all highway 23-24mpg depending on speed. normally get 20mpg with the combination of driving I do. my mpg varies and is directly related to my foot.

I like my 4:10's and you will be running 200rpm less than me at 70mph because of the trany difference.

at least go 3:73's if you are getting a gear, 3:55's just dont seem worth the money to change.


For as 4:10's being gas hogs, I was told I would only get 12mpg after my gear change. It wasnt that extreme, but there was a minor difference

MustangMafia

I would imagine lower (higher numerically) gears would give you better mileage in town, as the engine wont have to work as hard to get the car moving. As soon as I my girlfriend (who lives 20 miles of highway away from me) gets her liscense and I dont have to go pick her up. I am going to get 4.10s. To me it doesnt seem worth paying $500+ to from 3.27 to anything less than 3.90


Just my $0.02

blackbetty01

3.55's are good gears but truthfully you really won't notice much of a difference. Think about it 3.27-3.55 thats only about .28's of a turn so you'll be lucky to shave .2 off of your quarter is my guess. If you are getting gears the least you should go with are 3.73's.

n/a_threat

I have 3.55 stock in my car, and like them for my setup now, but when I'm done, I'll have 4.10s. FYI -- FRPP doesn't make 3.90s.

BadBob99GTConv

Motive makes 3.90's I think(although my shop said dont get them, but you will hear many different opinions). Anything less would be a waste of money.

xx9gt6xx

3:55's came stock in 03 GT's? Are you sure? I may be wrong but w/e...

But anyway, just like everyone said it's not worth the money to swap out a gear for only 3:55's. AT LEAST get 3:73's but you can't beat 4:10's...

MustangMafia

I very strongly doubt that going from 3.27-3.55 would save off .2 from your quatermile. .2 is quite a bit of time. And the reason the Cobra R has a ratio of 3.55 is because it was designed for more than straight-line performance. If you're just gonna be racing on the street/strip, then you can't really go wrong with 4.10's. The reason I might do 4.10s is I will eventually want have taller tires in the rear, and once I do that I will try to get my ratio closer to 3.90.

xxkazp3rxx

3.55 came stock in the 2005 GT's... and the 03-04 Mach 1. I got my 3.90's and I love em, I like em better then my stepbrothers 4.10's... I get around 16-18 MPG depending on how im driving on that tank and got low 20's with majority of highway driving (23 or so), I also have the mods listed below. Yes, Motive makes the 3.90 - If you don't want that 4.10's get something like 3.73 or 3.90 - while theres not much of a differance between 3.90 and a 4.10 - you still may like it. I chose them because I couldn't choose between a 3.73 and a 4.10... if you really want 3.55 I have a set of 3.55 from a 2003 mach 1 with around 3k miles on em.

BadBob99GTConv

OK, the post said the 2000 Cobra R, so I thought thats what he owned, which had 3.55's I think. 99 and up Mustangs had 3.27's. 96-98 had 2.73's or 3.27's as an option. Your profile says you have 04GT? If so, go 4.10's. At 75mph Im at 2400rpm(with 3.73's, so add 300 or so) with my 5 speed, but I have full exhaust, which believe it or not dropped my rpms on the highway 200 rpm due to less back pressure I guess. Anyone feel free to correct my year/gear combos as Im not 100% on all that.