mustang8719

Some times you have to change the gear on the speedo cable to tune it in.All the other gearing is in the speedo assy. itself.

nemethjames1

i bought the speedo unit as an assembly, it was already calibrated to match the 140, 85 mph ones.... say you have a 85 mph one in your car, and you put a 140, or 160, or 180, or even 200... its still going to be calibrated, because the calibration is inside the speedo assy.... only need to recalibrate when you mess with diff ratio or trans ratio's