I raced a guy I know that had 373 against my car wich was almost completly stock at the time.same year car and both lx coupes.he was so busy switching gears and fish tailing I beat him by a full car lenght 3 times in a row and he had some cash invested in his engine.I guess my car was built on a wednesday.If I were to by a set...355's
But also consider transmission gears. Factory or after market?? Auto or stick?(5 or 6spd??)
Rear axle shafts. Factory or after market?? Some shafts have different spline sizes. If this is a daily driver, spline size, tire size, transmission may not matter to you. I guess it is your call.
I have a 95 stang with a 351 roughly 400hp, 5spd Tremec Quick Ratio trans, with 3.55 auburn posi trac rear end. 3.55's seem to work pretty good with this setup.
I also read earlier in this thread, someone asking about changing gears in there driveway. To many posts to read them all. Not sure if anyone replied yet, but here is my .02
If you have never messed with gears, don't attempt, unless you have close supervision by someone who has expierence. You need a good torque wrench, you need to set backlash, and pre-load, and you need to check contact pattern. Who ever helps, or if you take it to a shop, should know these terms, and should know what I am talking about. If they don't, do I would not let them work on my car! Just my opinion.
I love my 3.55's. Pulls nicely in all gears. Although I have never driven a Stang with 3.73's, so I don't know the comaprison. Just my 2 cents
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88 GT, K&N, MAC equal length headers, High flow catted H-Pipe, Dynomax catback, Dynomax Ultraflow mufflers, Bilstein struts/shocks, Energy polyurathane rear bushings, MAC subframe connectors, MAC strut tower brace, MAC G-Load brace, Ford R. Super Duty 5 spd., Ford R. Auburn LSD, Ford R. Rear disc brakes, Ford R. 3.55:1 gears, Taylor 8mm. wires, 17" x 8.5" ROH wheels, Yokohama 255/45 ZR tires, LX rear lights, MOMO steering wheel, RECARO sport drivers seat.
With and overdrive gear in your trans, realistically all the worries you hear over gas mileage, engine runs too fast, can't go like 250 MPH , they're way over blown. With an OD trans in the car. Gears are the way to go......... You just can't beat em for bang for the buck and great take off.
Probably only two downsides to 3.55 and higher gears over the 3.08 and lower for street driving ......
1) The change in RPMs in terms of what's the "resonance" RPM in your cars exhaust system (when it resonates and gets loud) and hopefully the changing doesn't throw it right into your cruise RPM range.
and probably more importantly and what will affect you the most on the street every day.....
2) How does it affect your shift points. With an automatic, no big deal. But with a 5-speed, the shift points will be lower. The 94-95s have a really low 3.35 first gear (can't remember the 1st gear number for the earlier cars offhand, 2.95 I think). With a 3.35 first and 3.73 rear, shifting at 15 MPH will be at 2451 RPM while shifting at only 20 MPH (only 5 MPH higher) will be at 3568 RPM. Kinda high! Like you keep hearing, 1st is almost useless as in it winds up so fast you feel like as soon as you let the clutch out, you're pushing it right back in to go for a speed shift for second. Lets say you pick a common 2400 RPM shift point, the 3.08s would be at 17.8 MPH when you press the clutch pedal, the 3.55s at 15.4 MPH, and with the 3.73s you'd be at 14.7 MPH. A difference of 2.7 MPH doesn't seem like much of a difference. But, it's the rate of increase or speed at which the motors RPMs are increasing that creates an issue. You don't automatically and immediately hit the next gear (like and auto) so you have some time lag in between shifts. (Again we're talking daily driving on the street, not racing). With 3.08s the difference while you're shifting between 15 and 20 MPH is 674 RPMs, with 3.73s the 5 MPH difference increases to 1117 RPMs (2451 to 3568 RPMs). Really not much room left to go up any more without winding the crap out of the motor....
The larger the gear the the harder the launch! But remember the downside. The more gear you put in, the lower and now faster your shifts will have to be....... everytime you stop, all day long, every day, both direction back and forth to wherever you're going!
I have '91 AOD (automatic) with 150k+ miles and just had 3.73s installed on Friday. All I have to say is... SO MUCH BETTER! Why didn't ford make that the stock gear for the automatic fox body?
I was very worried about higher RPMs especially on the freeway ( i drive the southern california freeways all the time... to work and back), but as long as your consistent cruising speed isn't 90mph+ then you will be just fine. I constantly go 80mph and the RPMs are around 2500+ (barely pressing the pedal)
The engine seems to love the lower gears as well. Before it would seem like it was bogging down or strained, but now it feels like a brand new engine and doesn't hesistate to get up and go at anytime.
The shift points are much better all around. I used to find myself bogged down in third around non-freeway streets, but now third is fierce and ready to move. Going up hills and all around driving has been EXTREMELY improved.
And the gas mileage has actually seemed to get better. I am finding myself to be barely pressing on the pedal at all times, but when I do.... !!!
I am soo glad everyone (including some books) convinced me to get 3.73s for my AOD versus 3.55s! I think I would have been a little bummed putting 3.55s in, because 3.73s are frigging perfect.
ps. got subframe connectors (cheap) installed and I could definitely tell that they stiffened up the ride.... so now I am really having fun
I really hate to bring an old post back but I read a bunch of the posts and I still dont know what to do. I have a 2000 Mustang GT manual. I dont care at all about gas milege. Its my daily summer driver. I use it in the city 30 to 60mph at the most and on highways up to 90mph unless im raceing. I go to a lot of car shows and I drag race whenever its available. I just bought the car October 27 this year so its all stock right now. I plan to keep this car for a long time and really upgrade it. I mean from a k&N filter all the way up to a supercharger some day. My question to you guys is what do these gears do and why are they so recommended to upgrade first and also whats the best for how I drive. 3.55, 3.75, or 4.10?
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2000 Laser Red Mustang GT
Check it out at www.cardomain .com/ride/2170105
This thread helped me alot with my discision to get 3.73's it's one of the first mods that I wanna do to the car on top of what previous owners have done, and the sub frame connectors to make it more rigid.
With and overdrive gear in your trans, realistically all the worries you hear over gas mileage, engine runs too fast, can't go like 250 MPH , they're way over blown. With an OD trans in the car. Gears are the way to go......... You just can't beat em for bang for the buck and great take off.
Probably only two downsides to 3.55 and higher gears over the 3.08 and lower for street driving ......
1) The change in RPMs in terms of what's the "resonance" RPM in your cars exhaust system (when it resonates and gets loud) and hopefully the changing doesn't throw it right into your cruise RPM range.
and probably more importantly and what will affect you the most on the street every day.....
2) How does it affect your shift points. With an automatic, no big deal. But with a 5-speed, the shift points will be lower. The 94-95s have a really low 3.35 first gear (can't remember the 1st gear number for the earlier cars offhand, 2.95 I think). With a 3.35 first and 3.73 rear, shifting at 15 MPH will be at 2451 RPM while shifting at only 20 MPH (only 5 MPH higher) will be at 3568 RPM. Kinda high! Like you keep hearing, 1st is almost useless as in it winds up so fast you feel like as soon as you let the clutch out, you're pushing it right back in to go for a speed shift for second. Lets say you pick a common 2400 RPM shift point, the 3.08s would be at 17.8 MPH when you press the clutch pedal, the 3.55s at 15.4 MPH, and with the 3.73s you'd be at 14.7 MPH. A difference of 2.7 MPH doesn't seem like much of a difference. But, it's the rate of increase or speed at which the motors RPMs are increasing that creates an issue. You don't automatically and immediately hit the next gear (like and auto) so you have some time lag in between shifts. (Again we're talking daily driving on the street, not racing). With 3.08s the difference while you're shifting between 15 and 20 MPH is 674 RPMs, with 3.73s the 5 MPH difference increases to 1117 RPMs (2451 to 3568 RPMs). Really not much room left to go up any more without winding the crap out of the motor....
The larger the gear the the harder the launch! But remember the downside. The more gear you put in, the lower and now faster your shifts will have to be....... everytime you stop, all day long, every day, both direction back and forth to wherever you're going!
Well, I think you just turned me off from 3.73's for a daily driver (manual). I mean, in stop and go traffic, I dont want to be burning out everytime I stop. But out of curiosity the examples you provided, would that be based around a stock 5.0? How would these ratios be affected by a more powerful car? What I'm trying to find is a gear that will be fun to drive, IE when I do want to spin em across an intersection I can, but not every red light. Would 3.55's be way to go?
I myself have 3.55s installed with my 5-speed with the 3.35 first gear. I'm real happy with them and do not regret going with the 3.55s instead of the 3.73s.
No, you don't have to worry, even with a stock motor the 3.55s will allow you to break the tires loose to "show off" if you want.
The issue with the 3.73s isn't that you'll be "frying the tires" every time you leave the light, it's just that you'll be shifting so quickly that it will get old real fast as a daily driver. 1st gear winds up so fast that you'll essentially be shifting to second almost as soon as you've finished letting out the clutch for first gear. With the 3.55s, daily driving on the street, I myself usually shift out of first gear at about 3000 RPMs and that's at about 18-19 MPH. In other words not all that long after going into first. I personally wouldn't want any more than the 3.55s for this reason.
This whole gear choice thing can become a very heated topic sometimes!! You'll hear alot about "don't fear the gear" and yes gearing can give you a great kick in the seat and they're great for the track! But, without offending anyone, I do want to throw out the suggestion that street/daily driving does require you to keep things in perspective. My personal experience with 3.55s, a 3.35 first geared tranny, and 25.7" diameter 245/45/17 tires would lend my suggestion of not going with more than a 3.55 gear from a driveability standpoint for a daily/street driven car......
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95 GT w/ stock 5-Speed and 3.55 FRPP gears. KB underdrive pulleys. MAC unequal length headers with Flowmaster catback and stock cats/H pipe. K&N filter. Aluminum clutch quadrant. Hurst Billet Plus shifter w/ HD clutch. Stock heads, intake, and TB. 95 Cobra 17x9s w/ Toyo Proxes. Pioneer 550 watt w/ 10" sub.
66 Mustang Convertible. Owner since 1979. Original code 76C bench seat convertible. 289 4 barrel. Automatic. 3.25 Trac-Loc. P/S. P/B. A/C. Power top. Rally Pac. S/S wheels.
Oook well that has just put me back between getting 3.55's and 3.73's. My 1987 GT Mustang (Manual) has exhaust, upgraded cam, short shifter so would I still be able to smoke my tires when I felt like it? and if I got 3.73's would I really have to shift really fast all the time?
Thanks
3.55 rear gear x 3.35 trans first gear = 11.89 total gear multiplication.
Assuming your '87 only has a 2.95 first gear, 3.73 x 2.95 = 11.00 total.
What's this mean? If you do have a 2.95 first gear, you can put in 3.73s and will actually have less "total" gear, in first gear, than I do with only 3.55s! This means I actually have more torque multiplication (and will have to shift sooner too) than you will with 3.73s! So if I had a transmission with a 2.95 first, I'd probably go with the 3.73s. But.....
There is a down side to 3.73s with either transmission. (I'm pretty sure the '87 and '95 both have the same ratios in 2nd thru overdrive). The difference now comes down to how does the ratio affect 2nd, 3rd, 4th, and overdrive. In those upper gears yes with 3.73s you'll have more torque multiplication than with 3.55s. But, with 3.73s you'll be shifting sooner than with 3.55s and you'll be running a higher RPM for any given MPH.
Tire diameter affects all this too. Think of using a long 1/2" breaker bar vs a short 1/4" ratchet. The 1/2" breaker bar has a much larger turning radius. Which one takes less effort to turn a big bolt? (Which one makes for less effort on your part or gives less resistance to your force applied). Tire diameter works like this but in reverse. The larger the tire diameter, the larger the turning radius. The larger the radius, the more "resistance" to your motors torque. (So why go with a bigger tire? One reason, a bigger tire usually allows for a larger "contact patch" to the ground). So with tall tires you'll need more gear to go with them to get the same "torque" to the ground vs a smaller tire. They won't be turning as fast as a smaller tire though.
With a smaller diameter tire, you'll have less turning radius or "resistance" so you'll be able to put more torque to the ground compared to a larger diameter tire using the same final gear ratio. You'll have more "torque" to the ground, but, with a smaller diameter tire, your tires and therfore your motors RPMS will be "turning" faster at a given MPH than the taller tire. Everything has a plus and a minus to it.
Everything goes together as a "complete packge". To just say 3.55s or 3.73s are the "right gear" is too simple. Each choice is unique to a given application. You have to do some math, do your homework, and then make an educated decision.
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95 GT w/ stock 5-Speed and 3.55 FRPP gears. KB underdrive pulleys. MAC unequal length headers with Flowmaster catback and stock cats/H pipe. K&N filter. Aluminum clutch quadrant. Hurst Billet Plus shifter w/ HD clutch. Stock heads, intake, and TB. 95 Cobra 17x9s w/ Toyo Proxes. Pioneer 550 watt w/ 10" sub.
66 Mustang Convertible. Owner since 1979. Original code 76C bench seat convertible. 289 4 barrel. Automatic. 3.25 Trac-Loc. P/S. P/B. A/C. Power top. Rally Pac. S/S wheels.
