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Discussion Starter · #1 ·
I have a Dynamic C4 in my 94' mustang, with 3:73 gears, and BFG drags 255/50/16s which I think are 26.1" tall. Which speedo gear tooth count would I need. Right now it seems to be reading @ 15-17 mph fast at highway speeds. Thanks in advance for any info.
 

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A 21tooth i think is as close as you'll get from memory .Not sure if you can get any more teeth than that


http://www.c6-c4.com/

Some are listed on here or an adaptor box

<font size=-1>[ This Message was edited by: gregaust on 6/13/06 12:53pm ]</font>
 

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Depends what your output shaft count is. There are 7 , 8 and 9 "tooth" output shafts for the C4. I have a 7 tooth which is somewhat rare I guess and I use a 19 tooth driven gear. With a 30 inch tire its right on the money. One tooth difference on the drive gear will make a major difference in the driven gear selection.
 

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Discussion Starter · #4 ·
Thanks for the killer link. I'm not sure which drive gear I have. I plugged in 8, and it says I need a 23 tooth, which I didn't see listed. I can't remember off the top of head which one I have now. It was for my 5 speed with the same rear gear and tire, and it read @ 5 mph fast with the 5 speed. I think it's the redish brown one. My speedo doesn't use a cable, it has a couple of wires on it. So I guess I could use the box? What is the most common drive gear? I'm sure, since this is a Dynamic tranny, it is one of the more easily acquired cores. Thanks for the help guys.
 

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Whoever Dynamic is they are a rebuilder that most likely uses whatever cores are available and that includes output shafts. You cant assume that its a 8 tooth shaft. Most are but without pulling the extension and counting the teeth on the shaft you cant be sure. You could just run down to Ford and pick up a few different gears and do it through trial and error but if it is an 8 tooth shaft you wont be dead on the money. Thats the reason I bought a 7 tooth shaft before I built the C4 thats in my cougar . Its because I needed the nonexistant 22 tooth gear. The adaptor boxes work well if you dont want to go through the hassle. Just get going a known speed with someone else at your side with an accurate speedo then record your speed as shown on your speedometer. They'll send you exactly the drive adaptor you need and if I remember right their pretty cheap too.

The 23 tooth gears are known for wearing out VERY quickly BTW. Like 10,000 or less miles. The C6 gear will fit the C4. Thyere the same.
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<font size=-1>[ This Message was edited by: chipmechanic on 6/14/06 1:05am ]</font>
 
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