Speedometer Gear

[Robdogg67]

I 'm ordering a new speedo gear today and trying to determine which gear is for my setup. I'm familiar with the gear selector formula but I'm not sure what number of drive teeth (tranny output shaft) to enter. I have no way of checking under my vehicle right now.
My setup is this: 67 fastback with stock C4 (rebuilt), 3.50 rear, 25.7" tire dia.

Does anyone have a guess as to what was the most common # of drive teeth for the 67 C4? Thanks for any input.

 

[crushnut]

Ford drive gears are machined into the output shaft on C3/C4/C5/C6 & AOD transmissions. The only way to know for sure is to remove your tailhousing and determine how many drive teeth your transmission has. Probably not what you wanted to hear sorry. Hopefully someone else here will know. Good Luck

 

[HistoricMustang]

Are not these things different colors? Do you have the original?

HistoricMustang
www.historicmustang.com

 

[D.Hearne]

All C-4's had either 7 or 8 teeth machined into the output shaft Can't recall which right off hand. Just pull the speedo cable and see which gear is on it now and order a replacement.