Speedometer Gear Question

[66StangFastback]

I just went from 2.8:1 gears to some 3.55s and have found (using my GPS) the the speedometer is WAY off. I know I need to change the speedometer gear, but don't know what kind to buy or how to change it.

The car has the Ford C4 3 speed auto transmission, and 215/70r14 tires on it, with newly installed 3.55:1 gears.

What speedo gear do I need and how do I put it in?

 

[rbohm]

assuming a 7 tooth drive gear, you need a 20 tooth driven gear.

 

[suki243]

I have a similar problem with my 66, I was on the freeway and i looked at the speedometer and it told me i was goin 70+ but i was at the same speed as a big rig up ahead and everyone was passing me

 

[66StangFastback]

assuming a 7 tooth drive gear, you need a 20 tooth driven gear.

How do I find out the number of teeth in my drive gear?

 

[suki243]

Check this out
http://forums.stangnet.com/showthread.php?t=484151
http://www.tciauto.com/Products/TechInfo/speedo_gears.asp#FORD

 

[66StangFastback]

Thanks suki.

I guess I just need to know the number of teeth on the "drive gear"

 

[rbohm]

pull the driven head from the trans, and count the teeth on the shaft. most likely the trans you have will have 7 drive teeth.