97 Cobra speedo calibration

[Riocobravert]

My car seems to defy common wisdom. the speedometer was accurate when I bought it. The car had 4:10 gears , they were making noise, so I took it to Randy's ring and pinion. They replaced them with 3:31's (they didn't have the 3:27's). I ordered a new pink 19 tooth driven speedometer gear for it, assuming the gear had been replaced with a 23 tooth. When I went to put in the 19 tooth I was surprised to see that the one in the car was still the original 19 tooth gear. There doesn't appear to be a speedcal installed. I lifted out the shift bezel to see if I could see same wires coming through (nothing there). I can't see a little black box. The speedometer seems to be about 20% slow. Any thoughts on how this speed was calibrated for the 4:10's/ how I calibrate it back?

 

[stang dreamer]

im sure the diablosport predator has a function for speedo calibration, it does on my 98 anyway. if you have one use that and fiddle with the settings, see what it comes up with

 

[Riocobravert]

I don't see a model for the 96- 98's, could I get your model #?

 

[Riocobravert]

Everyone says the 97 is different from the 98, I'm not so sure but I went and bought a 16 tooth today, as small as they make according to the Ford parts guy. That got it closer, it's only off by about 6% now, speedo says 56 mph at 60 mph.