ford will release a kit with 4.10 gears ,exhaust and tune.check it out


http://www.fordracingparts.com/announcements/news05.asp

 

Cool. Last year's gears should fit already, it is the same 8.8inch rear axle, I imagine little or nothing will have to be done to the short shifters either to get them to fit.

 

I just got back from the shop where I had 4.10 installed on my 2005 GT / Auto. It made a huge performance gain as well as off the line performance.

 

I can't quite understand how Ford can ditch your factory warranty if their dealer installs these parts. Maybe I can, but I wish it didn't.

 

Hey there 2005redgt, I have a question for you because I am getting the Auto tranny as well. How has the 410 gears effected your gas mileage and do you know the rpm difference between the stock gears and your new ones say at around 70 to 75 mph? I have enver changed gears in a car before so I don't know the driveability difference and this will be my daily driver?

 

Automatic
Stock 3.31 gears - OD
65 MPH - 1,900 RPM
75 MPH - 2,200 RPM
85 MPH - 2,500 PRM

3.73 gears - OD
65 MPH - 2,130 RPM
75 MPH - 2,460 RPM
85 MPH - 2,790 PRM

4.10 gears - OD
65 MPH - 2,340 RPM
75 MPH - 2,700 RPM
85 MPH - 3,060 PRM

Manual
Stock 3.55 gears - OD
65 MPH - 1,770 RPM
75 MPH - 2,040 RPM
85 MPH - 2,310 PRM

4.10 gears - OD
65 MPH - 2,050 RPM
75 MPH - 2,360 RPM
85 MPH - 2,670 PRM

IMHO, 4.10s are perfect for a manual tannie GT, but are too much for an auto.

With and auto trannie, I'd go with 3.73s, especially if you do a lot of highway driving and have an automatic

 

Your car sounds amazing from what you have written out. Could you please post some pictures for us?

 

Thanks for the info V10, I do some highway driving and that was one of my concerns. I thought the mustangs came with the 3:55 rearend though? Do you think it is even worth going from stock to a 3:73 will there be enough of a performance difference to justify the cost?

 

It's not worth going to 3.73 from 3.55...you will notice very little difference. Keep it stock or go for the 4.10s. I don't think the 4.10s will be too much for the auto as stated above.

 

I agree with V-10. Go with the 3.73 with the auto. Remember, the autos come with 3.31's from the factory.

The Boss Hog

 

That's kind of what I thought but V10 has the stock gears listed at 3:31 not 3:55. I am positive the stock gears are 3:55 and to go just to 3:73 wouldn't be worth that little difference. I guess my decision has to be whether or not to sacrafice that must gas mileage at the 4:10's or just leave them stock.

 

Thanks Boss Hog, I guess I was wrong. I really thought the stock gears were 3:55 not 3:31. If that is the case than I would definitely make the leap to the 3:73. Do you know for sure the autos have a 3:31 stock??

 

It has been raining here in TX for days - so when it dries (tomorrow) I will post some additional pics with the lowering kit, etc.

 

Yes, only the GT manuals come with the 3.55's.

http://forums.bradbarnett.net/index.php?showtopic=9680

The Boss Hog

 

Boss Hog ( and me ) are correct ONLY the GT Manual trannies come with 3.55 gears. All other Stangs, V8 GT, V6 auto, V6 manual come with 3.31 gears.

When changing gears DO NOT focus ONLY on the numerical ratios. What is MORE important is the % change to the new ratio.

On an auto GT, going from 3.31 gears to 3.73s is a 13% increase.
On an auto GT, going from 3.31 gears to 4.10s is a 24% increase.

On a manual GT going from 3.55 gears to 4.10s is a 15% increase.

Putting 4.10 gears in an auto GT would be the same as putting 4.40 gears in a manual GT.

Stating it another way, putting 3.73s in an auto GT will be almost the same as putting 4.10s in a manual GT.

 

Thanks so much V10, I understand exactly the rationale. I think going with the 3:73 for the auto would be perfect now, the 4:10 would be way too much and also eat up a lot more gas on the freeway. Thanks for all the insights and help, that's why I joined this board!!

 

I'd like to change my 3.55 to 4.10 someday. I think if I do though, I'd like to pair it with a 6 speed tranny...$$$$$

 

With 4.10 gears (and a tune) :

- at 65 MPH with 2200 RPM @ 24.5 MPG
- at 80 MPH with 2500 RPM @ 21.5 MPG

Both of these are with normal, semi-aggressive driving.

 

Hey Bryan, your rpms are closer to what v-10 calculated for a manual trans. Whats up with that? Your rpms make the 4.10 gears look tempting for an auto.

 

Hey distortion, He has taller rear tires and that is probably the difference.