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Old 03-15-2005, 06:30 PM
cleanLX cleanLX is offline
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C6, rear gear change, speedo gear ?

anyone one know what speedo gear I need when going from 3.54's to 3.73's?
stock 8.75*16.5 tires.
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Old 03-16-2005, 06:37 AM
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Pull the speedo cable out of the tranny, and count the number of teeth on the gear or look for something like 16T (the number of teeth) on the end. I think you will need a one number (tooth) higher for a .25 different ratio change.

John
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Old 03-16-2005, 08:09 AM
dbossman dbossman is offline
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check out these links

These mustang sites have info that will help.

http://www.428cobrajet.com/speedo-calc.html

http://www.boss302.com/speedo.htm


Tim
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Old 03-16-2005, 02:43 PM
cleanLX cleanLX is offline
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cool.
so, a 8.75x16.5 tire is 29.5" tall...
I used 245/70-16 tire size, which is a 29.5" tall tire for the calculator...

Tire circumference: 92.68927 inches
Optimal driven/drive ratio: 2.54973

Closest matching ratio (difference of 0.04973): 2.5
Driven gear: 20 teeth, C8SZ-17271-B (Orange)
Drive gear: 8 teeth, part of transmission output shaft


The 3.73's are noticable over the 3.54's... nothing silly, but, I like them.
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Old 03-22-2005, 10:34 PM
cleanLX cleanLX is offline
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well.
I picked up the 20 tooth plastic gear and crawled under to make the swap.

Much to my suprise, the gear in the tail housing is steel, and rather long, no c-clip, the square inner cable exttends directly into the steel gear casting.

What am I to do now?
Where would I find one of these steel units?
Mine had D21 stamed on it. guess I should have checked to see if that meant 21 teeth...
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Old 03-22-2005, 10:34 PM
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