I used the VDO Electronic Speedometer in my Cobra and loved it. They use a Hall Effect Sending unit and can easily be adjusted when you change tire sizes, gears, or anything else that will cause the reading to change. And mine was accurate to the exact MPH per the CHP radar at 50, 60, 70, and 80 MPH. The tach reading was also right on at those speeds. I could care less about the car looking original as nothing about it was even close. And I wanted something that was easy to use and worked more than a few weeks or months before failing. I had my car almost 7 years and never a gage problem.
Ron
