3.08 to 3.55 worth it?

[Daryl]

Is the cost worth the benefit/result? How much difference will I se and feel going from 3.08 rear gears to 3.55’s? I don’t want to go ape-shit with3.73, 4.10 or 4.56 gears, but I wouldn’t mind a little more “punch” off the line, especially since my tired ass 5.0 is weak on 2 cylinders!
I went on LMR website and calculated cost for parts(gears kit, new diff cover with gasket, fluids, etc and new speedo gear) at roughly $800. Seemed reasonable... IF the benefit is worth the cost?

 

[evilcw311]

That’s what I’m stepping up to. Better gear for a turbo car. Go too much more and 1st becomes worthless.


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[Daryl]

Well, I junked my outdated SC and am
just running CAI. I’m also wondering if the 3.55’s will run considerably higher rpm’s in each
gear, especially 4th and 5th. I’m pretty light on the go fast pedal and I do like getting as much mpg as possible... but there definitely are times when I throw all that caution out the wind and get after it,.. ‘cuz my right foot and my libido/testosterone likes it!

It’s a vicious dichotomy!

 

[evilcw311]

Well, I junked my outdated SC and am
just running CAI. I’m also wondering if the 3.55’s will run considerably higher rpm’s in each
gear, especially 4th and 5th. I’m pretty light on the go fast pedal and I do like getting as much mpg as possible... but there definitely are times when I throw all that caution out the wind and get after it,.. ‘cuz my right foot and my libido/testosterone likes it!

It’s a vicious dichotomy!

When you say you junked it, please tell me you at least sold it!?! Like, you didn’t actually just junk it did you????


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[BJ98Cobra]

I put 3.73 in my 98 Cobra, it really woke the car up, get into power range RPM much quicker. Not really that much of a drivability issue. Still can use 1st geat, it just rev up faster. I'd go with the 3.55 if you plan to Turbo of SC your stang.

 

[PinkieT]

I like to pinch pennies when I can. Depending on where you live and how much in a hurry you are, maybe keep an eye on people parting cars out. I bought an entire Cobra rear including brakes and 3.73s for half your parts price and swapped it in my 5 spd 98 GT. Really woke it up, made it a lot more fun to drive.

 

[Daryl]

When you say you junked it, please tell me you at least sold it!?! Like, you didn’t actually just junk it did you????


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Ok, wrong choice of words. Yes, I sold it.

 

[evilcw311]

Ok, wrong choice of words. Yes, I sold it.

Yeah I would of had to stopped talking to you otherwise!!!!!! [emoji1787]


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[Daryl]

Yeah I would of had to stopped talking to you otherwise!!!!!! [emoji1787]


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I understand. I would have done the same!
FWIW, sold it for less than advertised. Kid, 17, bought it because he’s saving up to get “an old Mustang “. I could tell he didn’t have much and he probably saved up a good while, so I couldn’t help but cut a future Mustang fanatic a break. Help usher him into the lunacy!!

 

[Rons95GT]

I have had a 3.55 in my ‘95 for 20 years. I liked it before and after I upgraded my engine and then added a SC. I can cruise at 70mph about 2200 rpm or so.

 

[apsmith49921]

I'm pretty sure my cobra has 3.55s in it. 60 at 1900... I'm gonna swap them out for 4.10s if you aren't in a hurry I'd probably sell them to you cheap lol

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[96blak54]

I went from a 2:73 to a 3:55.....much mo better! Although the 5.4l torque output favored the airplane gear, the gear swap made the car more fun

 

[Wmac]

When this topic used to pop up, people would say, "don't fear the gear" If you are n/a then 3.73 with a 5 speed and 4.10 for an aode.

I have an auto n/a and went from 2.73 to 3.55 back in the early 2000's. Runs about 1800 rpm at 60mph. Nice street/ highway gear. Not ideal for the track. Couple years ago, went 31 spline, cobra diff with 4.10. Now runs about 2250 rpm at 60 mph. Thru the traps about 52/5300 rpm. Bang's the fuel limiter on the 1/2 shift and touches it on the 2/3 shift. The stock limiter on an aode is about 5300 rom. With a mail order chip setting the limiter at 5900 rpm its now just perfect out the back door. Exactly what I wanted for a fun stret car.

So with a 5 speed with a 3.35 first gear, 3.73 gear will put a smile on your. (n/a of course)

Just my thoughts. Those that said "don't fear the gear" knew what was required.

 

[Daryl]

I feel like an idiot, but what is “n/a”?

 

[Daryl]

I'm pretty sure my cobra has 3.55s in it. 60 at 1900... I'm gonna swap them out for 4.10s if you aren't in a hurry I'd probably sell them to you cheap lol

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Hmmmm, that could work! If possible, please find out for sure and confirm the 3.55 gear ratio and how many miles on them. Of course, examine for cracks, fractures, chips, scrapes and chips.
I don’t know enough about rear gear assembly but of the number of splines on the axle shaft matters, I would need to know that, too to make sure they’ll work with what I have!
Thanks!!

 

[evilcw311]

I feel like an idiot, but what is “n/a”?

N/A Naturally Aspirated


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[Daryl]

Thank you!

 

[Flade]

I'm pretty sure my cobra has 3.55s in it. 60 at 1900... I'm gonna swap them out for 4.10s if you aren't in a hurry I'd probably sell them to you cheap lol

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I have a set of 4.10 from a 97 Cobra if you are looking for a set.

 

[apsmith49921]

I'll keep that in mind. Working currently on the exhaust. I'll get back to you probably around the end of the month and see if you still have them.

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[sluggish94]

Ive had 2.73, 3.08, and 4.10s in a 5-speed Mustang
I have 3.55s in my heavy AOD equipped car.

2.73 was the most garbage for "feeling the speed" but I could hook from a dig off of idle real nice. Could hit 70mph in 2nd. Allegedly.

3.08 isn't too far off from the 2.73s. Just a touch better on the highway for my driving style.

3.55s in the AOD car make it peppy. It's a very neutral gear. It's like a dad gear. It wants to be cool with you but aint gonna give too much.

4.10 straight up ripped around the city. It's not for the weak. You'll be in third before you cross the intersection.

Your entire combination and end goal should determine your gear choice. If you don't know wether you'll stay NA or do any type of forced induction, you're on the right track with choosing the 3.55 gear. Just as an example, my Mustang had 4.10s in it when it had the nitous set-up. Now I'm stepping down to 3.27s cause I went Forced Induction and I can't build boost in first or second. My Grand Marquis has 3.55s but I'm stepping up to 4.30s cause it doesn't make any power, so I'm choosing that gear to compensate for a lack of power. Like I said, the entire combination plays a part in gear selection. To answer your question directly the benefit/result in going from a 3.08 to a 3.55 is worth the cost. That cost could vary depending on if you buy new or used. Don't know if you'll be able to *see* a difference, but you'll definitely feel the difference in a major way.