That jay car is for electric speedos our cars were blessed with mechanical speedo drives.

Try speedscreen in vic- it's as accurate as you will get and save $100 to $200 compared to a technician. Also if you change tyre size or profile or diff ratio measure the rotations again and send it to them- $30 and they change the 4 gears inside it to read true once more. Still shead of the so called guage technicians price