Choosing The Correct Coil Over Springs For Your 1979-04 Mustang

Created by Jay Walling / 7 min read
Date Created: 10/30/2015
Last Updated: 3/16/2023

Late Model Restoration answers some of the top Fox Body & SN95 coilover springs conversion questions to help you get the correct kit for your 1979-04 Mustang!

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Mustang Front Coilover Conversion Guide - Mustang Front Coilover Conversion Guide

Often times we at LMR hear the issues that customers have when it comes to choosing the best front and rear coilover spring set up for their 1979-04 Mustang. While this can be a simple solution, we felt that there wasn't a lot of info out there to better help the customer in their decision. We built this guide so that you the customer can get all of your questions answered so that you can get make an informed decision in your purchase.

Will Adding Coil Overs To My Mustang Make It Ride Rough?

With the right combination, a set of coil overs can actually improve ride quality. The difference is going to be in the kit that you choose. Follow below as we walk you through the perfect setup for your Mustang.

Benefits & Drawback Of Switching To A Coil-Over Front Suspension?

One of the most obvious benefits of coil-over setups is the ability to adjust the ride height to exactly where you want it with the included spanner wrench. Switching from factory springs or lowering springs to a coilover suspension results in better handling and performance for your style of driving. With the location of the coilover, these kits allow the use of wheel rates higher than those with a spring in the stock location. By utilizing this setup, you can reduce body roll and brake dive, resulting in a better-performing suspension.

Though not common, wheel and tire clearance problems can arise depending on offset, backspacing, and wheel size. One potential drawback is NVH, or Noise, Vibration, Harshness. With a coilover setup, you may experience more noises, vibrations, and a harsher ride as the suspension becomes stiffer.

Differences In Spring Rates And Sizes?

When choosing the right coilover kit for your Mustang, spring rates and spring sizes are very important and will be determined with how your car will be used. The higher the spring rate and shorter the spring, the less movement you will get from your suspension. For road racing where you do not want a lot of body roll, you would want a smaller spring and higher spring rates. If you are drag racing, you are going to want a longer spring and a lower spring rate to allow for better weight transfer. In the middle, you will find the perfect setup for street setups. Below, we will go over the different front and rear coilover springs rates such as drag racing, street driving, performance driving, and Auto X/Road Race.

Types Of Front Coilover Springs

  • Street/Strip Driving - LMR suggests a 12"-14" 150lb-200lb spring setup. These kits will give your drag Mustang great weight transfer for the strip. These spring rates will help with overall weight transfer on the drag strip. The taller springs used on these applications will allow the front end of the vehicle to raise and allow the rear end to squat more. If your Mustang is a drag strip only vehicle, then you will want to lean more towards the lighter end of the spectrum, 150lb-175lb with a taller 14" spring. For a daily driver that you occasionally take out on the weekend, the higher 175-200lb rates and 12" springs will be better suited for you.

  • Street Driving - LMR suggests a 12" 225lb-250lb spring setup. These kits will allow you to adjust your ride height and give you heightened handling characteristics. Normally, These rates will offer you the best overall ride quality for a daily driven street vehicle. If your main objective is a little of everything, this will be the option we recommend.

  • Performance Driving - LMR suggests a 10" 275-300lb spring setup. These kits will allow you to get better performance than a normal street kit but can still be used for light track use. Going with the 275lb or higher rates can heighten NVH and overall ride quality on the street. These applications would be recommended for occasional street use only.

  • Auto X & Road Race Driving - LMR suggests a 10" 350lb-400lb spring setup. These kits will perform greatly on the track for any auto x and road racing events. Ride quality will be sacrificed with these kits. If you are going this route, we recommend these to be for competition/off-road applications only.
Application Rate Description Spring Rates (lb/in) Spring Size (in)
Drag Racing Soft 150-200 12"-14"
Street Driving Mild 225-250 12"
Performance Driving Moderate 275-300 10"
Auto X & Road Race Driving Firm 350-400 10"

How To Choose The Correct Rear Spring Rate

Once you figure out the best front spring rate for your vehicle, you can then use a good rule-of-thumb to figure out the rear spring rate for either your 4-link (stock style) or Torque-arm rear suspension. This is done by subtracting the appropriate number from the front coil-over spring rate to determine the matching rear coil-over spring rate. Please be aware that the number used to subtract depends on your rear suspension type and your driving style.

Types Of Rear Coil Over Springs

Many manufacturers offer rear coilovers in two different applications. These will include a true coilover and a divorced setup. The ride height on divorced applications will be separated from the shock body on the rear of the car. These springs and adjusters will normally be located on the stock spring perch of the vehicle. With a true coilover, the adjuster sleeve and the spring will be directly attached to the shock body. Normally, most street applications will use a divorced style spring and adjuster. These also will offer less strain on the rear subframe and shock mounts for daily drive street use.

Mustang Front Coilover Conversion Guide - Mustang Front Coilover Conversion Guide

4-Link (Stock-Style) Rear Suspension

Application Number To Subtract From Front Coil-Over Spring Rate To Get Rear Coil-Over Rate
Street Driving 150
Any Performance Related Driving 125

Torque Arm Rear Suspension

Application Number To Subtract From Front Coil-Over Spring Rate To Get Rear Coil-Over Rate
Street Driving 125
Any Performance Related Driving 100

We at LMR hope this guide has better helped you with your decision in which coil over springs best suit your Mustang's build.

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About the Author

Jay has written content for Late Model Restoration for over 10 years, producing over 120 articles. Jay has an extensive 25-plus-year background in automotive and is a certified Ford Technician. Read more...