[66bluefb]

I just put a 1974 C-4 in my 66 Mustang. I used the old 66 C-4 gear on the end of the speed cable and the speedometer is running about 20 mph fast. I took out the gear and it has 17 teeth on it. That is a low number of teeth. I think they start at 16 and go up to 23. Does anyone know of a site I can go to that will give me details about how many teeth are on the tail shaft? The only numbers I could find on the tranny is C6AF7D027-B Thanks guys

 

[ixtlan]

You need to know your rearend ratio.
Then you can get the correct gear.

 

[66bluefb]

My rear end is 323

 

[gregaust]

A c4 has 8 teeth on the output shaft .You need a 20 or 21 tooth gears.

 

[66bluefb]

Thanks guys