New ride need help

[jsmoof]

Hey all I just bought a used 06 Roush. It has all kinds of stuff on it but my question is about the speed. It has 18" roush wheels (275-40-18 tires) up from the stock 235-55-17. It also has 4.10 gears also up from stock obviously. As far as the speedometer issue goes can a ford dealer re-calibrate this or do I have to buy a programmer to do it myself. It also has a ford racing 400 hp tune loaded in the ecm for the whipple sc. this recal wont affect the ecm tune will it????? Any help is appreciated.

 

[07 Boss]

I'm sure the dealership can do it, but you should get a tuner anyways. With the tuner all you have to do is enter the gear ratio and tire revolutions per mile and it will adjust the speedo for you. Doing this will not change any of the other parameters on your tune.