[wormster00]

Just got em installed today. NICE!! I'm having to do my mods slowly and I think for a first mod, the 4.10s were a great idea. The difference in acceleration is significant! I spun through 1st, 2nd and 3rd before I had to let out due to the fishtailing. The best is running about 45 in 3rd and punching it.

I'm ordering the tuner tomorrow to correct the speedo and get some extra oomph at the same time. Until it comes, I have a conversion I created using my handheld GPS unit. I have the stock tire size and no other mods (yet)...

Speedometer reading ---> Actual speed

30 --> 24
35 --> 28
40 --> 32
45 --> 37
50 --> 41
55 --> 45
60 --> 50
65 --> 54
70 --> 58
75 --> 62
80 --> 66

If you're traveling anywhere from 50 to 70 according to the speedo, a safe rule of thumb is to subtract 10 for actual speed. It's really a ratio... divide the speedo reading by 1.2 but who wants to handle a calculator, steering wheel and gear shifter all at the same time?

[GTron]

Considering 4.10s myself. Loved them in my 03.

[wormster00]

I was a little nervous b/c I've never been one to replace parts that are working fine. I LOVE the 4.10s though... I'll definitely have to upgrade to larger rear tires now.

Anyone have any ideas for tire sizes? I have the stock 17 inch rims and I guess 255's are the largest. Which brands do you guys like?

[The AdMan]

I saw on one of the vendor sites, motive 3.90s. I have an auto, do a split of highway and city, and at least 50 miles a day, 5 days a week. I'm concerend about losing the practicality, while trying to increase performance. I believe you can find a happy medium with these cars. Anyone try or hear anything about the motive gears?

[leebunnyz]

Originally Posted by The AdMan I saw on one of the vendor sites, motive 3.90s. I have an auto, do a split of highway and city, and at least 50 miles a day, 5 days a week. I'm concerend about losing the practicality, while trying to increase performance. I believe you can find a happy medium with these cars. Anyone try or hear anything about the motive gears?

i heard motive gears have a bad whine, you lose a couple highway miles but gain a couple city miles with gears. so since your doing 50/50 you will be fine

[Modern_Muscle]

which 17s do you have? Ive heard you can run 275 40 17s on the stock bullitts, at least, thats what ive got as my drag setup. black powdercoated factory bullitts with 26 x 11.5 x 17 mickey e.t. streets

[wormster00]

I still have the factory Pirellis (235/55 ZR17). I don't have the $ to upgrade the rims and most people say not to exceed 255 for width on the stock rims (17x8). MY problem is figuring out exactly which tire to get... I want something a little wider than stock and good performance but don't want to spend $700 for a set either...

Any suggestions for sizes and brands that fit the stock rims?

[stanglifemike]

Your also spinning your odometer more with the gears. Get that tuner quick. For tires, I love Nitto and stand by them 100%

[stanglifemike]

I meant to add its the 555 Nitto's that will work best for ya. You may even want to try the 555R for the rears. Thats their drag radial

[csredfire07]

4:10 are great. I love mine. But get the FRPP gears. Less likly to whine and 275/40's are the largest on the stock 18" bullits. I have the Falken 452's and love them too.

[The AdMan]

I spoke with someone yeterday at a local performance shop that deals with mustangs. The motive 3.90s are noisy in comparison to actual Ford gears. I can get the 4.10s installed (ford part) for less than $500 parts and labor with him. Catch is he highly suggested buying a tuner at the same time to calibrate the speedo. I really did not want to go for a tuner just yet. Ideas anyone?

[stanglifemike]

Get the tuner, its a great investment. I would reccomend going through Doug at Bamachips. He has the best tunes.

[The AdMan]

I keep reading doug at bama and brenspeed on this site. Not that I doubt the quality of work, I'm just having a hard time understanding how having someone dyno and tune my vehicle in person is any less quality than buying over the net.

[kmjsmith]

Go with a local dyno tuner...less time wasted waiting for Doug to get back to you...and Dyno tuning in my opinion is better, especially if he is local to you.

[TDog]

Can the speedo get adjusted properly for 4.10 gears with a tuner ?? I have 3.73's and wont get 4.10's unless my speedo matches it. What is the point if the speedo is that far off

[wormster00]

Yes, Tdog. The tuner will correct for the gears AND for different tire sizes...

I've only had my gears since MOnday but I love the accel. It gets you into the powerband much quicker.

I think I'm gonna order the JLT CAI and SCT 2 package from bamachips tonight. I don't want to be rolling up my odometer and quicker than necessary... AND I'm ready for my speedo to be right.

Thanks for the tire advice, stanglifemike. I'll check those out cause I'll be traveling a lot in July and need to get some new shoes for the baby...