3.90's or 3.73's Which one

pomag50 · Jul 26, 2007

I am looking into getting some new gears and I am definitely going to get some. I just can't decide which ones to get. I have my eye on some 3.90's is there much of a difference between those and the 3.73's? I am kind of stuck. Not knowing which way to go. A little help would be nice.

The Green GT · Jul 26, 2007

Check this out.

http://www.allfordmustangs.com/Detailed/608.shtml

pomag50 · Jul 26, 2007

i don't know how you get the ratios for the gears themselves. that is a killer calculator but I need some help finding out which gear ratios to plug in there. I just have a completely stock setup right now.

The Green GT · Jul 26, 2007

Put your tire size in, and where it says Rear Axle Ratio, put it to what gears you want to see and what speed you want to see what the RPM would be at. Everything is already set right if you have a stock 5-speed.

inphiniti · Jul 26, 2007

IMHO, i went to the race shop a few weeks ago... im pretty decent friends with the mechanics over there... i asked him for his honest opinion... he talked me OUT of 390s and told me to only do 373s... for the combo that i was gonna do, which is my friends set up he said 373s... its a DD for the time being and i dont wanna go too crazy down the line...

id probably stay in the 373 range...

pomag50 · Jul 26, 2007

ok that is all i wanted to hear. I think i will try and use the calculator another day when i have some time to sit down and look at it. I am not a huge math person anyway. I am sure it is easy to use and all but first hand knowledge goes a lot farther for me than a calculator. Since we all have the same basic engine and all i don't have to guess.

The Green GT · Jul 26, 2007

pomag50 said:
ok that is all i wanted to hear. I think i will try and use the calculator another day when i have some time to sit down and look at it. I am not a huge math person anyway. I am sure it is easy to use and all but first hand knowledge goes a lot farther for me than a calculator. Since we all have the same basic engine and all i don't have to guess.

I did a quick one for you. With the size tires on the site, at 75 MPH you will turn 2489 RPM in 5th with 3.737's, and 2603 RPM with 3.90's.

final5-0 · Jul 26, 2007

pomag50 said:
ok that is all i wanted to hear. I think i will try and use the calculator another day when i have some time to sit down and look at it. I am not a huge math person anyway. I am sure it is easy to use and all but first hand knowledge goes a lot farther for me than a calculator. Since we all have the same basic engine and all i don't have to guess.

True ... we all got a Stang and most have a 5.0
however
So many other things could influence your decision in this matter

You say you want some first hand knowledge

Well ... I'll give ya some real quick

I been here a long time

My first hand knowledge is based upon my time here
and
The way I've gotten to know a lot of my 94-95 StangNet friends

You could get the wool pulled over your eyes .......
before you even know it

Nobody would do it on purpose
but
We got those who like steep gears and those who don't
cause
We got those who got Stangs for all different kinds of applications

Some do the Weekend only thing
and
Some do the DD thing

Some are more into the 1/4 mile thing
and
Some are only into the Street thing

That math thing ... Its Your Friend :Word:

Heres the deal with the math

It strips away those different kinds of applications, opinions, hear say,
and other info that might mislead you with your gear
selection choice.

It can be so easy to get side tracked when you ask open ended Q's
on all these forums

However ... I'd would say this place is not too bad about that

Tell everybody your specific desires for your car
and
You'll get info that won't cause you disappointment in the long run

btw ... Welcome to the site

Grady

The Green GT · Jul 26, 2007

As far as daily drivers go, I love my 3.73s. I wouldnt want to go any higher. I do a good bit of highway driving.

sage2k · Jul 26, 2007

id do 3.90s or 4.10 if you ever intend on getting a head/cam/intake setup

pomag50 · Jul 26, 2007

for right now i think i am going to go with the 3.73's because i do a good bit of highway driving, eventually i want to set it up for the street. i am not so interested int eh 1/4 mile thing.

rj95svt · Jul 26, 2007

It sounds like the right choice for you! I have 3.73's in my car and I love them!!! It's by far the best mod I've done so far. I drive alot on the highway and I don't think I would want to go any lower right now. The 3.73's made the car feel much stronger and lighter.

94-302-vert · Jul 26, 2007

I do 50% highway (45 miles of highway a day). I wish I had 4.10s most days.

I vote 3.73 or 4.10 just to stay with FRPP gears...

final5-0 · Jul 26, 2007

Well I run 373's but I have many times wished I went with 410's

however

I'd not want 410's on a combo that had not extended its power band

cause

With power that peters out at 5K ... Just not all that effective

Grady

Pokageek · Jul 26, 2007

Depends on the combo. I think 3.73's are perfect for hard top, 3.90 for vert (mine - gave me good power and needed for a heavy vert). Just make sure you have good traction setup and you keep 1st gear. 3.73's FTW!

earleys94gt · Jul 26, 2007

3.73's for a manual
3.90's for an auto
But, like mentioned above, make sure what gear you choose goes with your combo. Nothing is more frustrating than buying the same part twice because you didn't research enough the first time.

pomag50 · Jul 26, 2007

Well right now I am bone stock. I wanted the gears to be first on the list of things to get because I know they are the best bang for you buck. I am thinking that 3.73's are the best option for me.

Black95GTS · Jul 27, 2007

3.90s are crap. Go with OEM quality Ford gears. Remember to take into account that your speedometer and odometer will now be off a significant factor, and you'll need to correct that via an electronic device like a SpeedCal.

Adam

Pokageek · Jul 27, 2007

Not to be disagreeable but what makes 3.90's so bad? I had them and liked them on the vert.

pomag50 · Jul 27, 2007

Thanks for the tip about the spedo and tach being off. I was not aware of that. And also i have heard really good thing about the Ford racing gears. I am kind of surprised no one mentioned that sooner.

3.90's or 3.73's Which one

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