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USA Standard 3.90 Gears (86-93 GT)

AmericanMuscle no longer carries the USA Standard 3.90 Gears (86-93 GT). Please check out 1979-1993 Foxbody Mustang Gears for an updated selection.
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$149.99

  • Item #21615G87
  • Market Price $169.99
  • You Save 12% ($20.00)
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AmericanMuscle no longer carries the USA Standard 3.90 Gears (86-93 GT). Please check out 1979-1993 Foxbody Mustang Gears for an updated selection.

Features
  • USA Standard Gear
  • Manufactured from 8620 gear steel
  • 3.90 gear ratio
  • 8.8" ring gear diameter
  • Fits 1986-1993 LX 5.0, GT, and SVT Cobra Mustangs
Description
Wake Up Your Pony. Installing a set of steeper gears is a great way to get your Mustang into the power band quicker for improved low end torque and faster acceleration off the line. A set of USA Standard Gears will really wake up your Pony. Better Than OEM Quality. Using state-of-of-the-art equipment and manufacturing techniques USA Standard Ring & Pinion sets are made to higher than OEM standards from high grade 8620 gear steel and are backed by a one year warranty.

Recommended Upgrade. Changing the rear axle gear ratio will throw off the calibration of your Mustangs speedometer, but a new Speedometer Gear is an inexpensive way to fix this issue.

Application. This USA Standard Gear 3.90 Ring and Pinion Gear set will fit all 1986 to 1993 V8 Mustangs including the GT, LX 5.0 and Cobra models. A master bearing kit is recommended by most installers, especially on high mileage vehicles, see drop down option above.

Technical Note. Installation costs will vary, but a good rule of thumb is between $250 and $300. Be sure to work with a reliable shop that you trust for installations.

Mustang Fitment: 1986 1987 1988 1989 1990 1991 1992 1993 Details

What's in the Box
  • (1) Ring gear
  • (1) Pinion gear
Installation Info
Tech Specs

Approximate RPM for 1986-1993 GT


Manual
Gear @25 MPH @35 MPH @45 MPH @55 MPH @65 MPH @75 MPH
1 4053 5674        
2 2393 3351 4308 5265 6223  
3 1600 2239 2879 3519 4159 4799
4 1203 1684 2165 2646 3127 3608
5 806 1128 1450 1773 2095 2417


Automatic
Gear @25 MPH @35 MPH @45 MPH @55 MPH @65 MPH @75 MPH
1 2886 4041 5196 6350    
2 1764 2470 3175 3881 4586 5292
3 1203 1684 2165 2646 3127 3608
4 802 1123 1443 1764 2085 2405
Fitment
  • Foxbody - 86, 87, 88, 89, 90, 91, 92, 93

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