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Anyone have 4:10's in the SGT yet?


SWEDESHELBY1

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I hope this has not been asked before, oh well.

 

I definately want the 4:10's. Without doing anything else that would launch my car better and drop my 1/4 mile .05 @ approx. 12.9-13.0 flat. That is almost better than putting in a supercharger for 1/4 mile times anyway. :P

 

Any responses from some one who's done it? What did it change your freeway RPMs @ 60 MPH?

What did it do to the gas mileage, like we care, but I need to ask it. What did it actually do for the 1/4 mile times really, is it true that 12.9-13.0 is the real deal? What was the cost from a reputable dealer or high end mod shop?

Thanks-

 

Swede

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I've wondered the same thing from someone with 4.10s and SAI S/C. Awesome combo, but I have to agree, there is something about getting the most out of N/A that is pure. Great post and question. Gears should run you about $225 plus lube and labor (if you don't install yourself).

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Stay tuned...... I'm having 4.10 gears installed tommorow morning. I have heard it like adding 50 hp and makes the car really JUMP. I'm looking forward to it.

 

 

Awesome I am looking forward to your post. I am very excited about the possibility of 4:10 being installed, thus leaving the warranty intact, as you can not with the S/C. B)

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Stay tuned...... I'm having 4.10 gears installed tommorow morning. I have heard it like adding 50 hp and makes the car really JUMP. I'm looking forward to it.

 

 

Gears cannot make horsepower, but they can certainly make better use of your horsepower in 1/4 mile!

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All, while you're at it, be sure to have them put on a nice polished differential cover too.

 

 

Adam - Do you really mean that? I would think you of all people would like to keep the car looking as stock as stock can get. Tell me your joking. B)

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Adam - Do you really mean that? I would think you of all people would like to keep the car looking as stock as stock can get. Tell me your joking. B)

 

 

I went with 3.73's in my GT500 and I wish I had gone to 4.10's, but I have a 6 speed gear box. Freeway rpm's at 60 mph went from 2200 in 5th to 2600in 5th with 3.73's; gas milage, well it sucks and always will regardless of the rear gears, I average 13.1 mpg.

 

Now my GT500 is putting down 560rwhp/540rwtq, it has always been hard to lock-up off the line with the stock rubber through 2nd gear...Now with 3.73's it's roast the tires real good!!! But where the 3.73's are noticable and fun is when you jump on it WOT rolling at 30mph in 2nd up to 80mph through 3rd, it just freakin' SCREAMS!!!!!!!!!!!! This is how I show my buddies that drive ricers what real American musscle can do, most of them grab for the armrest and get weak in the knees, bunch of ricer pussies!!!!!!!!!!!!

 

I've installed the new FRPP Mustang aluminum rear diff. cover with bearing cap supports (part #M4033G2), this one is in the 2007 FRPP catalog and they're about $200 and it's the only alum. diff. cover that will fit the S-197 Stangs; I also installed a Moser bearing cap stud kit (FRPP doesn't offer this kit anymore?). The gear swap cost me $500 which included the FRPP gears, a new pinion seal (because they ALWAYS get screwed-up when removing the pinion) and oil & fluid modulator.

 

Your results may vary, but if I were you, I'd go with the 4.10's ;)

 

Cheers,

WP

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I went with 3.73's in my GT500 and I wish I had gone to 4.10's, but I have a 6 speed gear box. Freeway rpm's at 60 mph went from 2200 in 5th to 2600in 5th with 3.73's; gas milage, well it sucks and always will regardless of the rear gears, I average 13.1 mpg.

 

Now my GT500 is putting down 560rwhp/540rwtq, it has always been hard to lock-up off the line with the stock rubber through 2nd gear...Now with 3.73's it's roast the tires real good!!! But where the 3.73's are noticable and fun is when you jump on it WOT rolling at 30mph in 2nd up to 80mph through 3rd, it just freakin' SCREAMS!!!!!!!!!!!! This is how I show my buddies that drive ricers what real American musscle can do, most of them grab for the armrest and get weak in the knees, bunch of ricer pussies!!!!!!!!!!!!

 

I've installed the new FRPP Mustang aluminum rear diff. cover with bearing cap supports (part #M4033G2), this one is in the 2007 FRPP catalog and they're about $200 and it's the only alum. diff. cover that will fit the S-197 Stangs; I also installed a Moser bearing cap stud kit (FRPP doesn't offer this kit anymore?). The gear swap cost me $500 which included the FRPP gears, a new pinion seal (because they ALWAYS get screwed-up when removing the pinion) and oil & fluid modulator.

 

Your results may vary, but if I were you, I'd go with the 4.10's ;)

 

Cheers,

WP

 

 

Thanks, I will go with the 4:10's unless you think the 3:73's are "almost" as good?. Were you at 3:55's before? What is the difference between the 3:73's and the 3:55's, I mean how did it feel was it noticable big time or just a taste? Oh I almost forgot- Hell of a post and to show the ricers what real American muscle is all about is a freekin bonus. B)

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I did some driving around tonight beofre the 4.10 gears are installed in the morning.

I got 80 mph / 2500 rpms in 5th gear

60mph / 2750 rms in 4th gear.

 

I will use these as a basis to see how much the rpms go up in 4th and 5th gears.

 

So there is no misunderstanding, I have read on other sites that the 4.10 change FEELS LIKE an extra 50 hp. In no means does it change hp, obviously. :blink:

 

stay tuned.

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Thanks, I will go with the 4:10's unless you think the 3:73's are "almost" as good?. Were you at 3:55's before? What is the difference between the 3:73's and the 3:55's, I mean how did it feel was it noticable big time or just a taste? Oh I almost forgot- Hell of a post and to show the ricers what real American muscle is all about is a freekin bonus. B)

 

 

Stock, the GT500 comes w/3:31's, the jump from 3:31's to 3:73's was very noticable; I'm not sure that you'd get, or feel, much difference going from 3:55's to 3:73's? I suppose you'd feel some, but bump it by 40-50 and you'll feel the difference for sure :D

 

Cheers,

WP

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I did some driving around tonight beofre the 4.10 gears are installed in the morning.

I got 80 mph / 2500 rpms in 5th gear

60mph / 2750 rms in 4th gear.

 

I will use these as a basis to see how much the rpms go up in 4th and 5th gears.

 

So there is no misunderstanding, I have read on other sites that the 4.10 change FEELS LIKE an extra 50 hp. In no means does it change hp, obviously. :blink:

 

stay tuned.

 

 

I completely understand what you meant. The car feels like 50 HP extra we all know that new rear gears does not make 50 EXTRA hp. That being said I waiting with baited breath to find out how you car is running er launching. B)

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I did some driving around tonight before the 4.10 gears are installed in the morning.

I got 80 mph / 2500 rpms in 5th gear

60mph / 2750 rms in 4th gear.

 

 

OK here are my impressions of the 4.10 gears on the SGT.

WHOOOOOOOOOOOOOOOOOOOOHOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOO!

Seriously, The car jumps out nicely in all gears. 1st is very quick of out the hole,( I would guess 60 ft times will be greatly improved) 2nd is less useful than before because if you really get on it, you could ramp up to the rev limited very quickly.I find myselft not spending much time in 2nd. 2nd is ma much shorter gear now. But 3rd is now better than before because there seems to be no dead rev range in that gear at all. 4th is very good also and I find myself using 5th more and I don’t downshift to 4th as often because 5th feels mush stronger.

 

The new rpm/speed specs are

 

80mph /5th gear/ 2750 rpms ---------------up approx. 250rpms

 

60 mph /4th gear /3100 rpms ------------- up approx. 350 rpms

 

My gas mileage hasn’t changed for about ¾ of a tank so far because I find myselfy using 5th more when before it didn’t feel very strong at all.

 

The best part is with the revs slightly higher, the whole car just wakes up and it gets into that wonderful muscle car sound in the power range quicker.

All I need to do is find a GT500 out there....beware! he is in for a surprise, at least for the 1st 3 gears! heheh

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You don't need to drive the car to answer the rpm difference question. All you need is a calculator.

 

From chevyhiperperformance.com.

 

I'm not at the office so I don't have the numbers you need handy, but I'm sure you can find them on the web.

 

Jim

 

 

 

Hot rodding is largely about relationships. No, we're not talking about the kind that your girlfriend or wife loves to discuss, but the optimal mechanical relationships for your car's performance. A few simple math formulas can help you select the right gear ratio and tire diameter to optimize your vehicle's performance. Because performance cars are often used for both street and track use, gearing a car to do both usually demands a compromise. Vehicle speed, engine rpm, overall gear ratio, and tire diameter are all related to a acceleration. For track use, an engine needs to operate within the rpm range where it makes the most power. For street use, optimal fuel economy and engine life warrant lower engine rpm. The good news is that, armed with some basic information, you can have a car that clocks impressive e.t.'s at the dragstrip and achieves plenty of low-rpm driveability on the freeway. Who said math was no fun?

What's in a Ratio?

 

An automobile uses gear ratios in both the transmission and the drive axle to multiply power. The two ratios multiplied together equal the final drive ratio. Spend a few minutes in any bench-racing session and soon you'll hear rear axle gear ratios discussed. For many performance cars, 3.73s and 4.10s are common gear choices. The rearend gear ratio refers to the relationship between the ring gear and the pinion gear. By simply dividing the ring gear tooth count by the pinion gear tooth count, the ratio is determined. For example, if we divide a ring gear with 41 teeth by a pinion gear with 10 teeth we find that the gear ratio is 4.10:1 (41/10 = 4.10).

 

Tire diameter will also have an effect on a vehicle's final drive ratio. As tire diameter changes, so will engine rpm at a given speed. We can demonstrate this with the simplified formula: rpm = (mph x final gear ratio x 336*) / tire diameter (*see "Formulas for Success" sidebar). For example, given 65 mph, a tire diameter of 30 inches, and a final gear ratio of 4.10, the engine speed will be approximately 2,984 rpm--(65 mph x 4.10 final gear ratio x 336) / 30-inch diameter tire. If we reduce the tire diameter to 25 inches, the engine speed increases to 3,581 rpm. By installing shorter tires, the vehicle will accelerate as though it has a 4.73 (higher numerically) gear without the expense of gear swapping.

 

Because transmissions are comprised of several gear choices, the transmission allows the vehicle to accelerate quickly with lower gears and to maintain a cruising rpm using higher gears. In the '60s and '70s, most transmissions offered three or four gears with a 1:1 high gear. Using a TH400 as an example, First gear is 2.48:1, Second gear is 1.48:1, and Third gear is 1:1. Multiplying the 2.48 First gear by the 4.10 rear axle results in a final drive ratio of 10.16:1 (2.48 x 4.10 = 10.16). For most street performance applications, a 10:1 final First gear ratio is usually considered optimal. The disadvantage of operating a 4.10:1 axle ratio on the street with a 1:1 high gear is excessive freeway engine speed.

 

Fortunately, today's transmissions frequently utilize Overdrive high gears in the neighborhood of 0.70:1, which allow reduced engine speeds. Combine these overdrive transmissions with a 4.10 axle ratio and you have a fuel-friendly final drive ratio of 2.87:1 (4.10 x 0.70 = 2.87) in high gear. A TH200-4R overdrive automatic utilizes a First gear of 2.74, a Second of 1.57, a Third of 1.00, and a 0.67 Overdrive. With this transmission's First gear ratio of 2.74 combined with a 3.73 axle ratio, the final drive ratio >> yields a 10.22 (2.74 x 3.73 = 10.22). In overdrive, the final drive ratio equates to a Bonneville-ready 2.49:1.

 

 

SIDE BAR refered to in the article:

Here are some handy formulas and examples to determine vehicle speed, engine rpm, and tire diameter. We've simplified these equations by replacing the constants of time, pi, and distance (as shown in the first mph formula) with the value 336. Remember that the final drive ratio is determined by multiplying the transmission's high gear ratio by the axle's gear ratio.

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OK here are my impressions of the 4.10 gears on the SGT.

WHOOOOOOOOOOOOOOOOOOOOHOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOO!

Seriously, The car jumps out nicely in all gears. 1st is very quick of out the hole,( I would guess 60 ft times will be greatly improved) 2nd is less useful than before because if you really get on it, you could ramp up to the rev limited very quickly.I find myselft not spending much time in 2nd. 2nd is ma much shorter gear now. But 3rd is now better than before because there seems to be no dead rev range in that gear at all. 4th is very good also and I find myself using 5th more and I don’t downshift to 4th as often because 5th feels mush stronger.

 

The new rpm/speed specs are

 

80mph /5th gear/ 2750 rpms ---------------up approx. 250rpms

 

60 mph /4th gear /3100 rpms ------------- up approx. 350 rpms

 

My gas mileage hasn’t changed for about ¾ of a tank so far because I find myselfy using 5th more when before it didn’t feel very strong at all.

 

The best part is with the revs slightly higher, the whole car just wakes up and it gets into that wonderful muscle car sound in the power range quicker.

All I need to do is find a GT500 out there....beware! he is in for a surprise, at least for the 1st 3 gears! heheh

 

 

 

Okay. Now tell me if you had to do it again what would you do 3:73's or the 4:10's? Also can the 4:10's be driven as a daily driver with ease of driving as well? What does it feel like coming out of the whole? What does it fell like at a rolling hole shot @ 20 mph? Lastly how much HP did you "feel" the you gained because of the 4:10 rear end gears? I love it!

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OK here are my impressions of the 4.10 gears on the SGT.

WHOOOOOOOOOOOOOOOOOOOOHOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOO!

Seriously, The car jumps out nicely in all gears. 1st is very quick of out the hole,( I would guess 60 ft times will be greatly improved) 2nd is less useful than before because if you really get on it, you could ramp up to the rev limited very quickly.I find myselft not spending much time in 2nd. 2nd is ma much shorter gear now. But 3rd is now better than before because there seems to be no dead rev range in that gear at all. 4th is very good also and I find myself using 5th more and I don't downshift to 4th as often because 5th feels mush stronger.

 

The new rpm/speed specs are

 

80mph /5th gear/ 2750 rpms ---------------up approx. 250rpms

 

60 mph /4th gear /3100 rpms ------------- up approx. 350 rpms

 

My gas mileage hasn't changed for about ¾ of a tank so far because I find myselfy using 5th more when before it didn't feel very strong at all.

 

The best part is with the revs slightly higher, the whole car just wakes up and it gets into that wonderful muscle car sound in the power range quicker.

All I need to do is find a GT500 out there....beware! he is in for a surprise, at least for the 1st 3 gears! heheh

 

Tim, that's awesome. Got your vmail too, that was funny.

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Okay. Now tell me if you had to do it again what would you do 3:73's or the 4:10's? Also can the 4:10's be driven as a daily driver with ease of driving as well? What does it feel like coming out of the whole? What does it fell like at a rolling hole shot @ 20 mph? Lastly how much HP did you "feel" the you gained because of the 4:10 rear end gears? I love it!

 

\OK answers....

Honestly, I never tried the 3.73s so how can I answer that one? I do like the 4.10 and for my driving it works. The difference btw the 3.55 stock and the 4.10 is MAJOR.

 

You can use it as a daily driver, I'm just not sure about gas mileage if you are temtped to get on it all the time. But the car can be driven lightly with the 4.10 gears.

Coming out the hole it feels strong in 1st. I save the burnouts for my S/C Harley truck with the automatic. I haven't done any burnouts for show in the SGT. I'd rather save the clutch. The car hooks up pretty good but remember, I'm not at a drag strip and that is whole different experience when the adrenlin starts pumping.

 

HP gains seems like 40-50 hp in the seat of your pants.

Oh Yeah remember, I have the SCT tuner so I needed to set it to the 4.10 rear end so the speedo would be correct.

 

Here's my summary of the 4.10 gears (I hope I don't get kicked off the forum for this but here goes.)

 

1st gear is good for pulling tree stumps out of your yard.

2nd gear is like a prom dress; looks and feels good but is off before you know it.

3rd gear is like a nice cold beer on a really hot day.

4th gear is like your wedding night it keeps going and going , going.

5th gear is like an old man in a rocking chair sitting on the porch...with a 357 Magnum under his blanket.

 

;)

Good Luck!

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Thanks for posting that. I was talking to Steve at SAI (if you have not been, take time to make a trip - it's great!) this past week and he suggested the 3.73's vs the 4.30's I was considering (especially since we were discussing the installation of a roots type blower aka Whipple). He said 3.73's were a better "all around gear" and suggested installing a 6 speed if you go any lower. After looking at the T56 ratios, I really don't see the need for that. I had decided to compromise with the 4.10's. I can see now I glad I did....

Can you post a 70 mph rpm? I really assumed the car would not be affected on gas mileage. All you're doing is moving it's mechanical advantage. Has 1st gear basically become useless for street driving? I assume you go to 2nd nearly as soon as you take off.

I may actually back down to the 3.73's now though since I need more highway driveability than strip... :)

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Stump, wouldn't you think a 6-speed be better suited for high gears such as 3.55, 3.27, or 3.08's? Maybe I need another cup of coffee this morning!

 

Harley, still curious if you noticed how much top end speed was sacrificed from 3.55s to 4.10s with your Steeda mods. I have basically the same setup minus the gears. I am happy for you though, you sound very excited and satisfied and that's what's it's all about in my opinion.

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Thanks for posting that. I was talking to Steve at SAI (if you have not been, take time to make a trip - it's great!) this past week and he suggested the 3.73's vs the 4.30's I was considering (especially since we were discussing the installation of a roots type blower aka Whipple). He said 3.73's were a better "all around gear" and suggested installing a 6 speed if you go any lower. After looking at the T56 ratios, I really don't see the need for that. I had decided to compromise with the 4.10's. I can see now I glad I did....

Can you post a 70 mph rpm? I really assumed the car would not be affected on gas mileage. All you're doing is moving it's mechanical advantage. Has 1st gear basically become useless for street driving? I assume you go to 2nd nearly as soon as you take off.

I may actually back down to the 3.73's now though since I need more highway driveability than strip... :)

 

 

70 mpg in 5th or 4th?

 

My overall gas mileage before and after is 17.4 mpg

 

1st gear isn't useless, it just has lots more pulling power. Afterall, how long do you stay in 1st anyway. 2nd is the only gear that is much shorter than before.

 

Stump, wouldn't you think a 6-speed be better suited for high gears such as 3.55, 3.27, or 3.08's? Maybe I need another cup of coffee this morning!

 

Harley, still curious if you noticed how much top end speed was sacrificed from 3.55s to 4.10s with your Steeda mods. I have basically the same setup minus the gears. I am happy for you though, you sound very excited and satisfied and that's what's it's all about in my opinion.

 

Savage, there really aren't many places in the Rhode Island roads to check top speed. too dangerous, you usually get it to about 110 or so and quickly run out of road around here. I prefer quick blasts without loking for a top speed. I may be crazy....but only so crazy! :blink:

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Stump, wouldn't you think a 6-speed be better suited for high gears such as 3.55, 3.27, or 3.08's? Maybe I need another cup of coffee this morning!

 

Harley, still curious if you noticed how much top end speed was sacrificed from 3.55s to 4.10s with your Steeda mods. I have basically the same setup minus the gears. I am happy for you though, you sound very excited and satisfied and that's what's it's all about in my opinion.

It might provide more streetability but it you compare the ratios of the T56 with the 3536 (? is that correct? I'm not awake yet) the T56 has a shorter 1st gear and winds up with the abuot the same OD gear in 6th gear. Yes it would be an improvement a little but for the cost of buying one then swaping it out IMO it would not be cost effective.

 

 

70 mpg in 5th or 4th?

 

My overall gas mileage before and after is 17.4 mpg

 

1st gear isn't useless, it just has lots more pulling power. Afterall, how long do you stay in 1st anyway. 2nd is the only gear that is much shorter than before.

Savage, there really aren't many places in the Rhode Island roads to check top speed. too dangerous, you usually get it to about 110 or so and quickly run out of road around here. I prefer quick blasts without loking for a top speed. I may be crazy....but only so crazy! :blink:

5th gear. I'm thinking somewhere between 2200-2400?

 

17.4 :o That was your BEFORE mileage????

 

We averaged 24.5 on a 3000+ mile trip and just driving it around we hit 19-20.

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5th gear. I'm thinking somewhere between 2200-2400?

 

17.4 :o That was your BEFORE mileage????

 

We averaged 24.5 on a 3000+ mile trip and just driving it around we hit 19-20.

 

70mph/5th gear is 2400rpms.

 

YEP BEFORE 17.4 ....it just changed to 17.3 this morning. Oh Well I guess I like to "get on it" from time to time. :unsure:

 

Agreed about the 6 speed, way too expense. My next step wil probably be FFR heads and Comp cams.

...saving my pennies....

 

;)

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I've had 4:10's 3:73's and 3:55's in my 04 Cobra, I'll take the 3:73's any day for all around performance and long distance driving. For just highway and all around driving the 3:55's seemed to be just fine. 4:10's great for the track but too steep a gear. Just my .02

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  • 1 month later...

I am in the market for the gear swap also. Always have been but was taken care of other things first. I talked with a CS8 owner and a Mustang tuner (going for a tune tomorrow). They both recommed the 4.10 even with the s/c. The CS8 owner who is an aftermarket (Shelby, Roush, Saleen, and others) dealer did say go 3.90 if I wanted to be conservative. He also mentioned that I might as well have the differntial done at the same time to save on labor because the car will spin tires easily.

 

Questions for those that have done and/or have expertise, I'd appreciate reasons also:

1. 4.10 or 3.90?

 

2. Are you having a harder time hooking up the rear with the 4.10?

 

3. Is the differntial going to be worth the extra money for the parts (it is the same labor with or without the differntial)?

 

4. The shop I called uses the Torsen T-2 system. Any experience or thoughts?

 

The car is used for weekend pleasure. Short and long hauls maybe a track day for fun but no competition.

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I read on another Mustang forum where a guy w/ a S/C switched to 4:10's, but switched back to 3:55's because he was running out of gear, or having to shift at a bad time, in the 1/4 mile. Whether that is valid info or not I have no idea.

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I read on another Mustang forum where a guy w/ a S/C switched to 4:10's, but switched back to 3:55's because he was running out of gear, or having to shift at a bad time, in the 1/4 mile. Whether that is valid info or not I have no idea.

 

 

Exactly why I would not go more than 3:73's. With our stock transmission gearing and adding the SC people just don't realize the difference in spool up.

 

Socal, gearing only. You don't need anything else. Just a ring and pinion and install kit plus labor. No need to change anything else for what you are utilizing you car for. For what it's worth, no matter what gear you put in it's how you plant the power that will reduce spinning tires. Many factors but not gearing. As for the diff. not in your case. They are doing what they do best. Sell parts and install. But that's just my .02.

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I appreciate the comments and I understand he is a sales guy. That is why I came for other opinions and will ask the tuner tomorrow, he doesn't sell or install parts.

 

As far as the 3.73, i had always been leaning that way because that seems to be the gear of choice for the other special edition cars that have superchargers. My question then is the improvement from 3.55 to 3.73 going to be worth the money?

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