likenew94stang

Ive heard that 3.55's will work well in my 5SPD GT. My car is a daily driver with some Highway travel and don't want to sacrifice all of my top end.

Are the 3.55's going to be nice for my car and will there be a noticable change in performance?

Tims 88GT

get a set of 3.73 and a 26inch tall tire, you will be just fine.

marx91

3.55's are a good all around gear, but you'll feel a bigger difference w/ 3.73's

QuickShortBus

I like 4.10s behind a manual trans personally, at 6000rpms with a stock height tire your top speed in fourth gear (or third with an auto) will be:

3.08 - 148
3.27 - 140
3.55 - 129
3.73 - 123
3.90 - 117
4.10 - 112
4.30 - 106
4.56 - 100

Keep in mind that with lower gear ratios your top speed will actually increase in 5th gear because you will be able to overcome aerodynamic drag.

Twisted

I just got my 3.55s in a couple of days ago. I LOVE THEM!! They are perfect for me--incredible improvement, yet still highway friendly. I don't regret choosing 3.55s.

EDIT--I guess I should mention that I'm running a smaller rear tire than stock, so my ratio is a bit lower than 3.55.

likenew94stang

I have 245/40/18's and 285/40/18 on the rear.

What kind of RPMs (roughly) would I be running at 70mph w/ 3.55s?

PRO50SC

Exactly. Just put a set of 3.55's in my wifes car. Major improvment over the stock 3.08's that were in it. You will be very please w/ the difference.

QuickShortBus

2100 in 5th and 3100 in 4th, by the way your tire is roughly 27" tall

Topspeed for 4th given your tires at 6000 rpm's is as follows:

3.08 - 156
3.27 - 147
3.55 - 136
3.73 - 129
3.90 - 123
4.10 - 117
4.30 - 112
4.56 - 106

For your tires at 70mph in 5th:

3.08 - 1800
3.27 - 1925
3.55 - 2100
3.73 - 2200
3.90 - 2300
4.10 - 2400
4.30 - 2550
4.56 - 2700

OnyxCobra

yep. i love mine also. Also why when someone says top end do most people think of top speed? When i hear top end i think about how well the car pulls itself through the end of the 1/4 mile, and also at higher speeds; in which case a lower gear will kill it where as with 3.55s you'll maintain fairly good "top end"

and im pretty sure at 70mph my RPMs are higher than 2100...

QuickShortBus

That was based on likenew's tires, they are just shy of 27" your stock tires should be around 25.6" which would account for the difference.