Might be a dumb question to some/all, but it isn't to me because I don't know the answer. I am putting 4.10's in my 02 GT tomorrow and know that my speedometer will be wrong. I have learned that things have changed since my 5.0 Fox days and things aren't as simple as a plastic speedo swap anymore. I also know that you can buy a speed calibrator and wire it in to fix the speedometer. I have been thinking of buying a tuner (SCT I guess) for my car and now I'm wondering if I do buy the tuner, will it recal. the speedometer and therefore make the speedcal device unnecessary? Thanks in advance for the help. I'm angling here to find a good reason why I need to buy the tuner instead of the other...two birds with one stone, etc.

 

yes if you buy a tuner it will fix your speedo and much more. I would go that route. Where ever you order it from gears will be one of the questions and you just say that you have 4.10's

 

Thanks Dave. I kept reading about adjusting the tuner for gear ratio, but wanted to make sure that meant not only for performance purposes. If a tuner will fix my speedometer and give me a little more giddyup...how can I go wrong?