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Discussion Starter · #1 ·
just finished the T5 swap into my 66 mustang, everything is great! But i guess i got the spedo gear, im on the freeway going about 80, and the speedometer is only reading 50mph. Im planing on getting 4.11's soon, but is there a way to adjust this without buying a new speedo gear? Because i am going to be changing from my stock 2.73 and my 4.11's when going on trips, and changind tires too, and i just want to be able to adjust the speedometer whenever. thanks
 

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yes and no. It is the easiest, you can go with gear reducers that are in-line of the cable, but you will have to go to a speedo shop and get it calibrated for both rear ends.

In my openion, take the car to the speedo shop and get dialed in, then when you change your rear to the 4.11's have it done again, just save the gear. If you are going to go thru all the trouble to change the rear gears and tires, the speedo gear will be a brease.

1 bolt, 1 clip, done deal.....
 

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I worked at a speedo shop many moons ago, it's a quick in and out process if you have the time. they will give you the actual speed readings thru out the range of your speedo. they will have all of the different gears so you don't have to go back and forth to the dealer ship for another gear.
 

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I'm curious as to what a "speedo shop" is. We have transmission shops, and rearend shops, but no "speedo" shops.
 

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All you need is a 5$ speedo gear, it is a plastic gear on the end of the speedo cable, I run 4:11`s and I use the white gear. It has the most teeth. Any tranny shop should be able to help you locate a speedo gear to match your rear end gears. It is about as cheap and accurate as it will get.
 

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If you want inexpensive and kind of accurate, go with the method that nastystang said. If you want expensive but dead on accurate, go with the adaptor method that slick mo fo talked about.
To answer nasalgoat's question, most automotive electronics(not stereo shops) places also calibrate automotive instruments.You can usually find them in the phone book under automotive electronics repair.
 

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"Speedo shop" they deal with guages, tachs, speedos, cruize controls, mostly instrumentation. like Jimbo said
 

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289 Mustang that is a killer link, it tells you exactly what you need, the speedo gear change can get you within 1 or 2 percent. As I said in an earlier post I run the white gear with my 4:11`s apparently it has 23 teeth, the teeth are very thin and this gear will not last long, I am on my third gear, going thru about 1 a year. This is common according to some folks I have talked to down here, so I just keep putting new gears on the end of the speedo cable, no big deal.
 

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I know, I just found it today. Couldn't wait to share it w/ others
 

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there are about 3 different gears to choose from, I think they are 13, 15, and 17.

Nastystang,
that gear shouldn't wear so fast, your cable might need some lube, or your speedo head might be to tight (needing service). It only drives a cable, which should turn freely, or your drive gear might be worn. Stick your finger in the hole and feel the gear, if it feels concaved it's worn, it should be flat. Unlike the Chevy (4 bolts), it's a pain in the ass to change, good thing gears are cheap.
 

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I have been told by a few folks that the teeth on those gears are so thin that they will wear very fast, but I agree with your assement as well, I am thinking I need a speedo cable because it is almost 38 years old, but for now I will keep changing plastic gears, I will fix cable when I do interior and paint. There are so many items that need to be looked at behind the dash and elsewhere that I will knock them all out at the same time.
 

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Discussion Starter · #15 ·
Hey nastystang, what size cam are you running to hit the 12.5's?
 

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Hey stang, if it's just the cable, pull it out at the top, and put it back with some grease on it. That could free it up quite a bit and it should only take 5 min.
 

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I will give that a try, to go along with the same theme my speedometer bounces around like cray too, it seems to be much better when the speedo gear is new, but it still bounces around, I mainly go by rpms anyway since my tach is in front of the speedometer anyway, but I can see 25 and 90 OK though.


Not that I would ever drive 90 mph.
 

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if it's bouncing, your cable might have softened up. try the lube, before buying a new cable.

*****************************
I had a feeling you didn't use it
 

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Andysam, the cam is a Comp Cams hydrolic roller grind.

.540 lift with .220 duration @ .050-Intake

.566 lift with .224 duration @ .050-Exhaust

110* LSA (lobe seperation angle)

It is not just the cam that got me in the 12`s, honestly it is not that aggressive, but I like it, if I could have done it a little different i would have gone for more duration on the intake, but I am not complaining, I really think that with some slicks I could be looking at some really low 12`s.

Maybe a Sneeky Pete to push me to 11.99.

And dont come back with out a "CAGE"
 
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