basically a steeper gear will get you into you power band quicker causing better acceleration. You need a tune to recalibrate the speedometer if its not mechanical. Overall its a great upgrade to any mustang.
i think 99 and newer need the tune but older is mechanical? not sure though
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-2000 Mustang GT Ford Racing 4.10s // T45R 5speed// Hawk HPS Brake Pads // Cold Air // BBK 75mm TB // BBK X-pipe // Hooker Aero Chambers // Eibach Sportline's // Ford Racing Upper and Maximum Motorsports Lower Control Arms // '95 Cobra R's // Toyo Proxes T1-S // Steeda Tri- Ax Ram HDX Clutch // tuned w/ SCT X3
Go with 3.73s if you do a lot of in town driving and highway driving... if you don't then get the 4.10s... but if its a daily driver i would go with 3.73s
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2006 Mustang - Ford Racing GT500 Dual Exhaust - Eibach Pro-Kit - Diablo Sport Tuner - BBK Intake -
Its like when you shift your 10 speed into the littlest sprocked in front and the biggest one in back. Your legs (the engine) will move easier with less effort, but they go faster/quicker (rpm's) so in a car, when you change to a shorter gear, the engine has more mechanical advantage, but too much mechanical advantage, and the engine rpms get too high for comfortable driving.
I'm goin with the 4.10's but that is only cuz I have an automatic, and taller than stock tires in back. If you have a manual go with the 3.73's
The acceleration difference is phenominal in a gear swap. I swaped my 2.79 gears in my fox body out to 3.55's and it felt like I added 100 hp. Bummer was, I didn't have an AOD and my freeway rpm's were like 3000-3500 at 60-70 mph. In an overdriven car, it won't be as bad. I expect to be around 2300 rpm at 60 after my gear install. That is confortable, and still has legs to get up to 100mph.
Its like when you shift your 10 speed into the littlest sprocked in front and the biggest one in back. Your legs (the engine) will move easier with less effort, but they go faster/quicker (rpm's) so in a car, when you change to a shorter gear, the engine has more mechanical advantage, but too much mechanical advantage, and the engine rpms get too high for comfortable driving.
I'm goin with the 4.10's but that is only cuz I have an automatic, and taller than stock tires in back. If you have a manual go with the 3.73's
The acceleration difference is phenominal in a gear swap. I swaped my 2.79 gears in my fox body out to 3.55's and it felt like I added 100 hp. Bummer was, I didn't have an AOD and my freeway rpm's were like 3000-3500 at 60-70 mph. In an overdriven car, it won't be as bad. I expect to be around 2300 rpm at 60 after my gear install. That is confortable, and still has legs to get up to 100mph.
Thanks man for breakin it down for me I wasnt to sure if i wanted to buy one or not. Is thier a brand that you recommend?
Buy used Ford OEM gears. The only other brand available anymore for the 7.5" rear is Motive, which has a tendency to whine even with a good install.
Either that or shop around for a take-off 8.8" rear end with the gear ratio of your choice. They're pretty cheap now and will save you the trouble of looking for a good installer to do the gear swap.
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Black 2005 Mustang v6, 5 speed, IUP, EUP and Leather.
Razzi 1/4 window scoops, Mustang GT Sway Bars, Flowmaster American Thunder Single Exhaust, Clear Front Turn Signal Lenses, Demolet CAI, X-cal2 91 tune, Hurst Comp/Plus Shifter, FRPP T-Lock, Ford 3.73 gears
(noob question) what are gears good for? 
