3.55 vs. 3.73 Gears

Pushrod

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I have 3.55's and according to that chart I should be going about 99 mph in 5th at 3,000 rpm's. I frequently hit 3,000 rpms in 5th on the interstate and there is no way I am doing 99mph. Do I have different gears in my tranny (original replaced by previous owner) or is my tach way off?
 
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95Doug5.0

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Nov 18, 2004
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Got FMS 3.73's today on Ebay for $81 plus shipping! Going to have them put in after Thanksgiving. I will post the track times before 3.73's and after. Thanks all for advice! :D
 

Leadsled Coupe

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Unless you’ve got a lightweight aluminum flywheel. Makes a huge difference.

There are many factors in deciding what rear gear ratio to install.

max ultimate HP

Tire size

Fraction time Hwy vs in town

Many factors I’ve missed as well. Fwiw I had 3.55s when I started 30 yrs ago in my ‘86 fox. Ultimately I swapped to 3.73s and found them much better for me.

“It all depends”.....
 

General karthief

wonder how much it would cost to ship you a pair
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Unless you’ve got a lightweight aluminum flywheel. Makes a huge difference.

There are many factors in deciding what rear gear ratio to install.

max ultimate HP

Tire size

Fraction time Hwy vs in town

Many factors I’ve missed as well. Fwiw I had 3.55s when I started 30 yrs ago in my ‘86 fox. Ultimately I swapped to 3.73s and found them much better for me.

“It all depends”.....
You are talking to ghosts, this thread is from 2004.
 

from6to8

There's suction so I used that end O_O
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Lol talking to ghosts. I actually just googled the topic and it led me here; I know he wasn't referring to me though but still funny. I just had 3.73's put in my 94 cobra after having 3.55's in my modded 95 gt in my avatar. The Gt/saleen definitely had more weight and maybe 3.73's I would have loved overall better for that car. As to this one at first I was like man dang around town and 35 mph ( me going actually maybe 38 sometimes) I don't want to be nearing having to shift into 5th gear lol. I've gotten used to it now though so it's all good. Also to mention I was like with the 3.55's I could play with the exhaust tone a little more as it relates to the rpms and burning more fuel vs the 3.73's and wanting to shift ; playing with the exhaust as in putting my neighbors or the public in AWWW:D:D.The 3.55's seemed more perfect to do that and everything was more proportionate in that regard as to the weight of the car with the 18's with huge tires and heavy ass SR race wing, ect. The 3.55 rear end will go in the other 95 which is the twin of the one in the avatar which got rear ended in 2015. That car will get a 351(400).
 

Noobz347

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I've more or less stopped playing with gears. A little fine-tuning one way or another to get cruize speeds in 4th and 5th might be nice.

One thing led to another in the engine bay until I ended up with enough torque and HP in the little Fox that I said, "Uncle" or "Enough" or "I'm going to die soon I should stop". It's a streetcar. It's still sporting the original 2:73s and traction is still a huge issue. LoL

I guess that the moral of my story is to spend your money on generating more torque. :D
 

MustangIIMatt

I need something stupid to play with
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4.10s or nothing, bow down peasants!

I mean, errr... umm.... carry on!
 

from6to8

There's suction so I used that end O_O
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I've more or less stopped playing with gears. A little fine-tuning one way or another to get cruize speeds in 4th and 5th might be nice.

One thing led to another in the engine bay until I ended up with enough torque and HP in the little Fox that I said, "Uncle" or "Enough" or "I'm going to die soon I should stop". It's a streetcar. It's still sporting the original 2:73s and traction is still a huge issue. LoL

I guess that the moral of my story is to spend your money on generating more torque. :D
I can see that moral lol. I guess with this 94 it's getting the engine that was in the other car. 291 hp with 306 ft lbs of torque. It will get LT's vs shorties though but everything else will remain the same. I will likely leave that setup in the car for a long long time and that's even @ 182 k miles on that block. I also have the 351 to build with the 95 and bought a Terminator July of 19 and so I have enough to mess with that I can afford to have each car's in levels of hp which was my goal anyway when my other car got hit in 2015.
Basically this car I'm glad I went with gearing it since it'll likely keep the 302 for awhile and I remeber how it was in my other car so i'll be glad for that little bit of a kick :D
 

rockyracoon

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Nov 23, 2005
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410s for more fun stop light to stop light. (Non aspirated)
Just how I see it. I mean if you're going to the trouble and expense of installing gears why not go with 410s ? And absolutely fms gears, especially if your doing your own install. I used the existing size pinion shim (good pattern) and they are just as quiet as the factory 308s were.
 
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HemiRick

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Jun 28, 2020
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Another fan of lower number gears here. My car was factory ordered w the 3.08 and I love it. I drove a 3.73 car once and it was crazy unless unless spinning tires was your goal. Even w the 3.08 gotta be real careful launching in 1st if you actually want to go. I'd say spend your $$ on motor/suspension/tires and gears wont matter. One thing no one on here seems to consider is motor life....the less rpms it turns the longer it lasts. Gears are a cheap way to make a real quick kick in the pants improvement, but long term, like loud exhaust get old IMHO.
 

rockyracoon

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Nov 23, 2005
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I guess some 94-95 GTs are more powerful than others however in stock form IMHO tire spinning takes some effort. I drove one back when it was allmost brand new and not much grunt. I've allways thought they needed much lower gears. Now if were talking 86-93 GTs well that's a different story. I had an 87 sd that had 273s and could chirp 4th gear. Also had a 93 that was fine with stock gears.