texasbluesdownunder

Hi all,
I have a C9 auto installed in my 66 coupe.It was changed for the original C4.The speedo is reading out about 10%.I have an 8" 3.00:1 rear end.
I have two other speedo cables,one with a purple cog and one with an off white cog.Can anyone tell me which cog is most like to be correct ? Or what colour I need ? I'd like to get it right if possible.The speed cameras are really bad down here in Australia !
Any help would be appreciated.
Thanks Ron

mustanglover66

I Found the formala to figure out the gear you need.
drivegear teeth * rear gear ratio * tire rotations per mile
1000
tire rotations per mile can be found in spec. from tire manufactures

tylerdru

What in the hell is a c9?

66 stang

really?

texasbluesdownunder

Thanks Mustanglover1966.I'll see if my maths comes out right.
B.t.w a C9 is very similar to a C10 except the dipstick comes out of the pan with a curve.The C10 comes straight out.I'm not sure if there are internal differences as well but they look very similar.
I think a C4,C9 and C10 are all very similar.
Ron

BillyBobJoe

sure its not a C6?

Soaring

Ford used the C9, C10, then the FMX. The problem, is that this is a classic section of Mustangs, and the C9 and 10's are a foreign langueage to us. You may want to post this on the 5.0 section for better results for an answer. Ah heck with it, I will just move it to the 5.0 section. Go there.

texasbluesdownunder

Well I've done the math and that formula works a treat regardless of whether it's a classic 'stang or not.
Thanks MUSTANGLOVER1966 !!
I actually have either the original C4 or a C10 (beefier C4 but looks the same externally) dipstick straight into the body.The C9 has a dipstick that curves into the pan.That's really info for Aussies as the C9 and C10 appear to be downunder models.
The formula works great and should be useful for any car though.
I had 17 teeth on my speedo cable cog which was 10% out.I have used the formula and installed a 19 tooth cog and all is well.
Good bye speed cameras :-)
Ron Downunder