There should be a speedometer calibration shop in your area. Probably used
by the local police too. I was told last time I had an issue with
calibration is to drive a measured 10 mile distance then note what your
speedo reads, using the difference they can put in the needed pieces parts
to make it read accurately.

"mustangGT_00" > wrote in message
lkaboutautos.com...
> Good day guys,
> I got 4.10 gears installed in my 00 GT. The speed odometer is not reading
> the actual speed. I know SpeedCal is the needed thing in here, but I'm
> just too busy with school and work. I talked to some people and it seems
> like I need an expert to talk to. Can any one help me with tips about this
> part (function, price, installation, etc..). Your help is appreciated.
> I Mak
>