I have had Ford Motorsport 3.55 gears put in my 1990 GT and it pushed the speedo 10 mph fast. I was given a black speedo drive gear to replace the white one in the gearbox, but this was not really any better. I have since fitted 17 inch wheels with 235/45/17 tyres and the speedo is now being ignored!! Does anyone know what type of gear I should be using??
The car is a 5 speed.
Cheers