speedometer gear

[Purple73Cuda]

I have 3.23s and F70-14 tires. I want to put G60-15s on the car. By the factory service manual, the speedo gear would be off by one tooth. How many MPHs would my speedo be off from being off by one tooth on the gear?

[Chryco Psycho]

2.5 %

[Purple73Cuda]

If the gear is one tooth more than it is supposed to be, would the speedo read faster or slower?

[tactransman]

Slower than actual.

[dodge freak 2]

Just get the right gear for it. Is quick to change and Mancin racing has them for around $20 each. Otherwise you will forget about it and go past a cop a few miles over and get pulled over for going 10 mph right on past him.

At least I would 

[Pale Rider]

...and Mancin racing has them for around $20 each...

Please help me out here, because I can't find it on the Mancini site. 
Summit Racing only seems to have GM and Ford gears.
And YearOne is pretty pricy: $69,95

[MEK-Dangerfield]

Please help me out here, because I can't find it on the Mancini site. 
Summit Racing only seems to have GM and Ford gears.
And YearOne is pretty pricy: $69,95

http://www.manciniracing.com/

[72rtchallenger]

yearone is priced wrong online,,you should call them,,i have last years catalog on cd from mopar nats last year and it says there $21

[tactransman]

I don't see them on Mancini. What number of teeth do you need,I can look at the shop and see if I have one?

[wally426ci]

Try the dealer, i paid $8

[Pale Rider]

I need the 33 teeth version (yellow)
Currently I have a 36/red one. Speedometer is almost 10% too slow. I have a 3.23 and 275/40 tire
Calculator says I need a 33 and the deviation of my speedo points in same direction.

Btw; I live in the Netherlands

[shadango]

Same issue here.....mind if I horn in a bit?

I read 30 when I am doing 35 (verified by gps)....that would be like 13% off!

Is that 2.5% figure correct for any number of teeth ?

Do you figure the percentage using the higher number or lower?

I used the higher number...35mph, and found that 30 mph is 14% lower than 35....divide by 2.5 and I get 5.6.... I need 5 or 6 fewer teeth, right?

I dont know what I have in there right now.....
does it just pull out of the tranny once you pull the speedo cable?

[tactransman]

does it just pull out of the tranny once you pull the speedo cable?

You remove the retaining fork and it pulls right out. Jack the back of the car up alot higher than the front and you should get no fluid leakage. The speedo adapter has to be indexed right for the number of teeth also when reinstalled.

[shadango]

You remove the retaining fork and it pulls right out. Jack the back of the car up alot higher than the front and you should get no fluid leakage. The speedo adapter has to be indexed right for the number of teeth also when reinstalled.

Good tip on the fluid thing....you lost me on the last part though.....

[tactransman]

You rotate the pinion adapter until the tooth range you're using is at the 6 o'clock position, as shown in the attached image.