speedo question

[jon79flavette]

hey guys, this is actully not a corvette question (my apology) but the premise is the same. I have a 79 vette that has the 140 mph speedo, and I have read some previous posts pertaning to the speedo upgrade on some 80-82 vettes to the 140 speedo. well I have an 88 GT mustang, i am giving to my son for his 16th b-day (yeah I know, I am crazy) we just installed the white face lenses, with the blue illumination. does anyone know if on a mustang, would there need to be a speedo recalibration, or a drive reduction gear of some sort at the tranny to the speedo cable that would bring the new 140 mph speedo correct??? I don't want to pull the dash apart twice!! Thanks guys

 

[JohnZ]

Nope, all speedo heads are calibrated for the same standard input cable speed; only thing you have to change is the driven gear at the trans if you change axle ratios or tire sizes.