I have a 2008 Ford Mustang with 3.55 gear ratio currently and I'm looking into changing the ratio to 3.73. My question is will I need to buy a Speedometer recalibration tool or should I get a tune or both? Any suggustions

 

You won't feel much of a difference going from 3.55 to 3.73

If you have a hand held tuner already you should be able to adjust the gear ration on that.

 

Maybe with how little the difference in gearing is, you'll notice better results sticking with the gears you have and buying a tuner/intake combo. Roughly the same price as gear/tuner combo.

 

+1 that you won't notice much difference going to 3.73. And yes, you'll need a handheld to correct the speedometer. If you don't have a CAI & custom tune yet, then ditch the gears. As stated, you'll feel a lot more difference from the tune.

 

If you want to gear higher and actually feel appreciable power when accelerating, you might want to look into buying 4.10:1 rear gears instead.

Other than that, for the money, just like what everyone else said above me, a CAI & tune will give you better feel of power.

The only other thing that will top that is a supercharger or turbo kit.

 

I agree as well with the rest, just did AM/Bama Race tune... you will def feel the diffrence.

 

You will need to calibrate your speed.