Hi everyone I appreciate any help I can get I have a 1993 five speed 5 L mustang with a T5 with 273 gears in the rear end the stock speedo gear should be a 18 tooth but when I put an 18 tooth in it the speedo reads 20 over so I put a 23 tooth in it and it reads 10 over I’m not sure why this is happening does anyone know how to fix this also I have the stock ponies with the stock tires size thanks for your time
Adam
Adam