As the story goes, I was able to find a Ford motorsports 160mph speedometer, and I want to put my actual mileage on it without breaking it. My current 85mph (car is an '87) displays 12xxx miles, and my new 160mph unit is displaying 37xxx miles, and well, I don't want to have to leave it hooked up to a drill for a month to make it roll over again. Any ideas? Thanks.