Don't take this the wrong way because I cant believe this is still being talked about and so much wrong info is being posted here is horrible. I am apologizing in advance
there are 2 ways to adjust your speedo/OD with a pre 99 car either calebrate the puter when you tune it, or go to ford and buy a tranny sensor gear (like 8-10 bucks) prolly a 25 or 27tooth and i think its the red gear you'll need, i have a 23tooth red gear for my 3.73's and its spot on. if its post 99 the only way is a tune
Again to clarify the wrong posts like the one above.
YOU CAN NOT CALIBRATE THE SPEEDOMETER ON ANY 94-98 5 SPEED BY USING A TUNE. THE SPEEDOMETER IS NOT ELECTRONIC LIKE THE 99+
You want the cheapest easiest route. Stop listening to people who recommend plastic tranny gears for 4.30's that wear out overtime and arent accurate. 4.10's is the steepest gear a plastic tranny6 gear is accurate for.
youwin said:
i own a pair of 98's a V6 and a GT both had 3.73's put in
the v6 had a stock rearend gear of 2.73 and its tranny gear was a 17 tooth
the GT had a stock rearend gear of 3.08 and its tranny gear was a 19 tooth
EDIT: if your car has the 3.27 rear gear option then the tranny gear will prolly be different
More reasoning not to go off of that guy and get a tranny gear. He is basing the reasoning off a GT with a 3.08 gear, which had to be a 5.0 with a T-5 and not a Modular 4V with a T-45, being they did away with the 3.08 gear and went to the option 3.27 in 96 for the GT.
The 96-01 Cobras came with a 3.27 gear standard! That is the starting gear, not a 2.73 or a 3.08.
Just get a Speedcal like the rest of the world, minimize confusion from posts that show nothing but confusion because those posting in it don't have a clue either.
BTW, they dont make a 275/45ZR 17 tire and just assuming the difference in tire/rim size will fix it is also ridiculous.
I am starting to doubt some of the advice on the site.