3:73 gears, what do you think about this?

[FXDL]

Go with 3.73's if you have an auto.

If you have a manual, go with 4.10s.

3.31 to 3.73 = 12.7% increase
3.55 to 4.10 = 15.5% increase
So the % increase will be similar.

Also keep in mind the OD ratio on the Auto is .71, while the manual has a .62 OD ratio.

3.73 x .71 = 2.65
4.10 x .62 = 2.54

So an auto with 3.73s will be pulling more RPMs on the highway than a manual with 4.10s

So it looks like you'd be pulling around 2500rpm at 75mph in a manual GT with 4.10 gears. That's not bad considering...

 

[Gt1995]

3.73's are mandatory on 5 speeds to me ?

 

[Zedoc]

... your @$$ ...actually experienced a car with a tall gear.
QUOTE]

I experienced one. My new '63 Sting Ray had a 4.56. Yes, it was great for laying a patch, but on a day to day basis less comfortable to live with and didn't have the feel of driving a locomotive that my '70 Formula 400 w/3.08 had. I'd say, you're driving an axle ratio rather than a motor.

 

[sapperstang78]

3.73's are a waste of money. You are already starting at 3.55's. that is only a 5% change. To really feel anything, you will need to go 10% or higher. The reason that there are so many that say 3.73's are great is because they probably started out with 3.27 gears (a la the 04 down Mustangs - except the Mach 1 - and the auto trannies). Now that these cars have 3.55's then you should AT LEAST go 3.90's but I would personally go with a 4.10 gears. I have done 3.73's and 4.10's and the 4.10's are MUCH better IMO and the gas milage does not really change that much - you stay in higher gears instead of having to downshift to pass.

Yep. going from 3.55 to 3.73 is one of the dumbest things I have heard. You really will feel NO difference. Go no less than 4.10.

 

[351CJ]

Yep. going from 3.55 to 3.73 is one of the dumbest things I have heard. You really will feel NO difference. Go no less than 4.10.

Read what has been posted. The original question was about 3.73 gears for an automatic. Automatics come with a 3.31 rear end NOT 3.55s.

 

[351CJ]

So it looks like you'd be pulling around 2500rpm at 75mph in a manual GT with 4.10 gears. That's not bad considering...

Actually it's even lLess RPMs:

Manual trannie, 4.10 gear, in OD @ 75 MPH = 2,360 RPM

Auto trannie, 3.73 gear in OD @ 75 MPH = 2,460 RPM

Which is why I said 4.10 for Manual, 3.73 for auto. If you don't do a lot of highway driving & long trips you could go as low a 3.90s with an auto (2,570 RPM in OD @ 75 MPH), but with 4.10s and an auto you'd be cranking 2,700 RPM @ 75 MPH and 3,060 RPM @ 85 MPH.

 

[LXXVICOBRA]

... your @$$ ...actually experienced a car with a tall gear.
QUOTE]

I experienced one. My new '63 Sting Ray had a 4.56. Yes, it was great for laying a patch, but on a day to day basis less comfortable to live with and didn't have the feel of driving a locomotive that my '70 Formula 400 w/3.08 had. I'd say, you're driving an axle ratio rather than a motor.

Zedoc:
I may be wrong, but I would suspect that the comparison between the '63 Sting Ray and the '05 Stang isn't necessarily a good one in this case. The Vette (I assume) was a 4 speed, whereas the stang (if manual) would be a 5 spd. And this isn't even considering the differences in the transmission gearing.
Even in an auto application(s) between then and now, wouldn't the lack of overdrive on the older cars would create a similar difference (and have an effect) in what would be considered practical as an ideal final drive ratio?

I agree with you entirely however, if your comments only pertained to say, 60's and 70's vintage cars. Back then, 4:11 was considered about max for practical everyday use with 4 speed and auto cars...and cars being modified with ratios of 3:55 to 3:70 or so were probably far more common, as it was a pretty large step from the tall 2:79 and 3:00 ratios of the era.
I personally prefer driving my old 4sp car with the mid to high 3 ratios any day, than what might be preferred on todays cars.

 

[sapperstang78]

Read what has been posted. The original question was about 3.73 gears for an automatic. Automatics come with a 3.31 rear end NOT 3.55s.

Ok. He should still go with 4.10.

 

[gilmoujr]

Someone used MPG as an excuse NOT to get 4.10's but I drove 500 miles with 3.55's in my Mach 1 and got 24.1 MPG and with the 4.10's (the same exact route) got 24.5. MPG is not an excuse because it actually can improve your gas mileage just like mine (maybe not in the city but definitely on the highway).