Thoughts on switching to 3:73 gears

[Frankycheechoo]

Just want some feed back on switching to 3:73 gear on a bolt on pullied . Is it ok and what about later when adding a bigger blower will the gear be too much at 600ho ish ? Any that this plz chime in
Thanks


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[robvas]

From 3.55? Hard to justify the cost unless you're rebuilding the whole thing with a new diff and axles etc

Then again if you're doing it yourself so you're just buying g the gears and fluid, go for it. 28" tire incoming!

 

[2003RedfireVert]

Not that big of a jump. Is this a street car? If so, keep the 3.55s.

 

[Albatross]

I’ve got a 3.73 with 700whp. I think it’s perfect. I say do it!

 

[Bdubbs]

I see no reason, at least on a higher hp car. I'd rather have more rpms in 4th gear trapping in the 140's.



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[1 Alibi 2]

14's came with 3.31's, useless for street driving.
I wanted 3.90's, but Ford doesn't make them any more, thought 4.10's overkill.
3.73's for me are perfect..
.

 

[ITSTOCK]

3.55's are the perfect all around gear. Waste of money going to a 3.73.

 

[FJohnny]

To summarize the above;

You would be foolish to do it. You would also be foolish not to do it.

Good luck with your decision!

 

[Albatross]

You would be foolish to do it. You would also be foolish not to do it.

Exactly.

 

[P49Y-CY]

i'm not sure whether it's the couple hundred extra pounds, but 3.73's in my vert was a great upgrade.

in my coupe i tried 4.10's and it was terrible. went back to the 3.55's and now it feels perfect.

~450 upper-pulley only street cars

 

[ITSTOCK]

i'm not sure whether it's the couple hundred extra pounds, but 3.73's in my vert was a great upgrade.

in my coupe i tried 4.10's and it was terrible. went back to the 3.55's and now it feels perfect.

~450 upper-pulley only street cars

In exactly what way did you have a great upgrade going from 3.55 to 3.73? The numerical difference with RPM and MPH is just not enough to make any practical difference at all. I mean, we are talking 1-4mph and 50-200rpm difference from first through fourth.

It just makes no difference with the powerband of a PD car like we have. It's all in your brain.

 

[BlckBox04]

I’m rockin 3:73’s whipple sra

 

[P49Y-CY]

In exactly what way did you have a great upgrade going from 3.55 to 3.73? The numerical difference with RPM and MPH is just not enough to make any practical difference at all. I mean, we are talking 1-4mph and 50-200rpm difference from first through fourth.

It just makes no difference with the powerband of a PD car like we have. It's all in your brain.

could be but i def noticed the difference down low

 

[cobracide]

I had 4.10s in my 2001 4v for obvious reasons. A NA 4v car really needs gears - that was a good mod. Totally different animal that needs huge gears. It also needed a six speed, but I digress..

Unless you are a really good driver and can moderate the torque at low RPMs without traction loss, hard to see a benefit going 3.73s with a Roots blower on a 2003 Cobra. Even less so after upgrading unless it's a centri blower.

I'm spinning way too easy on 3.55@527/510 from a dig. Maybe if you're building a highway queen and taking off from 60mph, that's different.

 

[Caden807]

I’ve got 4.10s in my car, makes right around 650. First gear is useless lol, will probably end up going 3.73

 

[01yellercobra]

If you're pulling the rear end apart and need new gears then it might be worth it. Especially if you're going to stay with the eaton for a long time. If you're thinking about doing it just to do it, I wouldn't bother. It's not cheap to do in the IRS.

Another thing is what is your plan for the car? Is it going to be a quarter mile car? Then yeah, change the gears and fine tune with tire height. If it's going to stay a 99% street car stick with the 3.55's.

I can honestly say I've never wished for more gear in my car.

 

[Frankycheechoo]

If you're pulling the rear end apart and need new gears then it might be worth it. Especially if you're going to stay with the eaton for a long time. If you're thinking about doing it just to do it, I wouldn't bother. It's not cheap to do in the IRS.

Another thing is what is your plan for the car? Is it going to be a quarter mile car? Then yeah, change the gears and fine tune with tire height. If it's going to stay a 99% street car stick with the 3.55's.

I can honestly say I've never wished for more gear in my car.

The plan is upgrade to bigger blower 2.3 perhaps 2.9 the goal is 600 ish . Im getting the irs done this year so figured while they are there .. . I will be going to the track at least once or twice a year cus last year was my first time and now i have the itch. I do feel it could use a little more gear just to get in 4th sooner . I do go for cruises too and like to do some highway pulls here and there .

 

[01yellercobra]

The 600hp will overcome the gearing pretty easily. I can just go by my experience. From an upper only eaton to the current 2.9 on E85 I've never wanted more gear. I will say I don't have as much fun at the track anymore because all I do is spin. But I do need a real tire under the car. The last time I went the R888R's didn't hook at all and I got a real good look at the wall.

 

[MG0h3]

3.55's are the perfect all around gear. Waste of money going to a 3.73.

What about running a 28” tire on 15s?

That’s my hang up on getting a drag pack.


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[TerminatoRS]

The 600hp will overcome the gearing pretty easily. I can just go by my experience. From an upper only eaton to the current 2.9 on E85 I've never wanted more gear.

This.^

+1 on 3.73s not worth the trouble. Maybe if you were coming from a 3.27...

Mine had 4.10s in it when I bought it. Bolt-on car around 460whp. Spin city. Sucked having to shift every 2.3 seconds when just cruising around town too. Eventually went back to 3.55s and 600hp...haven't regretted it once. Nice and easy on the highway at 70mph too.