1994-10 Ford Mustang Ford Racing Speed-Dial Speedometer Adjuster by Ford Racing

Mustang Ford Racing Speed-Dial Speedometer Adjuster (94-10)

Details   |  Description   |  Customer Photos   |  Reviews   |   Community Q&A
  • Ford Racing Mustang Speed-Dial Speedometer Adjuster (94-10) M-4209ADPT-AC
Mustang Ford Racing Speed-Dial Speedometer Adjuster (94-10)

Get youe speedometer back in the groove with this Ford Racing speed calibrator!

Item #M4209ADPTAC

Your Price: $144.99

Market Price:$196.00
You Save 35.18 % ($51.01)

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  • Allows for a corect speedometer on both manual & automatic transmission Mustang without the need to purchase an expensive tuner!


  • Easy Installation
  • Simple Adjustment
  • Corrects for rear gear & tire size changes
  • Fits 1994-2010 Mustang

What's in the Box

  • (1) FRPP Speed-Dial Speedometer Recalibrator
  • Installation Instructions

Product Description

The Ford Racing (FRPP) M-4209ADAPT-AC Speed-Dial Speeometer Adjuster/Recalibrator for 1994-2010 Mustang is used to correct your Mustangs speedometer because of tire size or rear gear ratio changes. No longer is it required to purchase a tuner to get your speedo working again!

This speedometer calibrator scales a frequency based on the vehicle speed signal up or down to maintain accurate vehicle speed indication to the instrument cluster and PCM.


1994-2004 Mustang with manual or automatic transmission

2005-2010 Mustang manual transmission

2005-2010 Mustang automatic, but is limited to equivalent of one step higher or lower gear change ratio (+/- 10% change). For example, if your 05 automatic has 3.31 rear gears stock, you can step up to a 3.55 & keep your speedo correct using this adjuster.

NOTE: To maintain cruise control function on 2005-2010 Mustang automatic and manual transmissions, gear change is limited to equivalent of 5% higher or lower ratio (<+/-5% change). For example, a gear change from 3.55 to 3.73 results in a gear ratio reduction of 4.8% so cruise control will continue to operate normally. A gear ratio change from 3.55 to 4.11 results in a gear ratio reduction of 13.6% so cruise control operation is lost.

Customer Photos (1)

Community Q&A

Product Reviews (4)

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4 reviews
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4 of 4 REVIEWS
4 of 4 REVIEWS

5 Stars   Easy install, works great!
By on 4/2/2014
Image uploaded by Chris B. Needed a way to recalibrate the speedometer on my 1996 Cobra when changing to 4.10 gears. Looked at other boxes on the market and they already had plugs to intercept the VSS negative wire down by the transmission. I liked the idea of being flexible with the mounting location.

The box came with limited directions that pointed you to Fordracingparts.com website to get the latest and full instructions. After pulling down the full PDF, the install sheet talked about alternate location under the hood, tapping in to the transmission harness. I did just that, easily locating the VSS negative wire and key on power in the transmission harness. Once I soldered the wires together (with heat shrink tubing) and retaped the harness, all I needed to do was find a good ground and the box was installed.

As you can see in the attached picture, I mounted the box to the firewall of the Cobra. Two stainless screws hold the box on and are easy to back out to be able to open the box up and change the settings.

Another reason for purchasing this box is the switch settings represent a % change from stock. There are 3 dial switches, each labeled 0-9. If you have stock tires and stock gears, the box would be set to 1-0-0 an interpretation of 1.00 change (no change in this case) of the gear ratio from stock, since you leave the stock speedometer gears in the transmission.

In my case, I put 4.10 gears in the rear, with stock sized tires and wheels. In my case I simply divided the stock ratio 3.27 by the new ratio 4.10 to get a 0.80 difference in ratios. Plugged 0-8-0 into the box and all is set. If you change wheels/tires and gears, a bit more math is required, but it is still a ratio change from stock that gets plugged into the box.

It has a test circuit that when all the dials are placed at 0-0-0 it will indicate a pre-determined MPH on your speedometer at rest. In the case of my 1996, it would indicate 45 MPH, which means the box is working correctly.

Overall a couple bucks more than other recal boxes, but I highly recommend for the ease of install options and settings.
From LatemodelRestoration.com®: Thank you for the very thorough review!
Yes, I would recommend this item to a friend!

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5 Stars   Excellent part!
By on 3/18/2014
I bought this part to correct my speedometer and it did exactly that! It was pretty simple to install and not hard to figure out how to adjust it.

Yes, I would recommend this item to a friend!

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5 Stars   Works Perfectly
By on 9/2/2014
Go to the Ford Racing site and get the instruction sheet there: http://fordracingparts.com/download/instructionsheets/FordInstShtM-4209ADPT-A.pdf

Follow the suggested under-hood alternate installation and this is a super-easy install. I had a ground strap connecting the hood right there by the connector with appropriate resistance, so it didn't get much easier. Tap the red power wire, splice green and white into the signal wire and run your ground and you're done. Do the math to set your controls and enjoy your correct speedometer. I was stunned how accurate it was when compared side by side to my GPS. The only down side is the price, which seems steep. But shipping was free and super-fast, so that helps. Very pleased.

Yes, I would recommend this item to a friend!

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5 Stars   Great Product
By on 8/5/2014
Fixed my speedometer after installing new gears. It was easy to install, with no problems at all. My only recommendation is to go Ford Racing web site and print out more detailed instructions, which were very helpful.

Yes, I would recommend this item to a friend!

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Vehicle Applications

Ford Mustang - 1994 (94) - 1995 (95) - 1996 (96) - 1997 (97) - 1998 (98) - 1999 (99) - 2000 (00) - 2001 (01) - 2002 (02) - 2003 (03) - 2004 (04) - 2005 (05) - 2006 (06) - 2007 (07) - 2008 (08) - 2009 (09) - 2010 (10)

About This Brand

Ford Racing
Ford Racing - Mustang Ford Racing Parts
Ford Racing is the leader in performance parts and accessories for Mustang and Ford Lightning.

LatemodelRestoration.com is proud to offer Ford Racing Performance Parts for your project. Ford Racing is dedicated to manufacturing the highest quality products offered in the industry. Choose from suspension, exhaust, wheels, and other performance parts at LatemodelRestoration.com. If you want the best for your Mustang or SVT Ligtning, look no further than Ford Racing Performance Parts!

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