Product Summary

  • These coil over springs are specifically designed for the Mustang II applications
  • Made a special chrome silicon spring material
  • Available in several spring rates to custom fit your project
  • Has a free height of 8.13" and both ends are square to ensure a proper fit
  • To be used with coil-over shocks and the factory upper spring pocket

Key Specs

MFG. Part #
BrandSpeedway Motors
Spring Rate

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  • Used with our AFCO and QA1 bolt-in Mustang II coilover shock conversions
  • Fully polished and chrome plated surface for show winning looks
  • Available in several spring rates to support most any frame and engine combination
  • Fits factory and aftermarket Mustang II applications with stock upper spring pocket
  • Special tapered spring fits stock upper spring pocket and standard 2-1/2 inch lower shock seat

Convert Your Existing Mustang II Front Suspension to Coilovers with Zero Modifications

Many Mustang II early adopters used an actual front suspension crossmember from the Mustang II or used an aftermarket budget or lower cost Mustang II IFS kit that usually end up with an OE-style fixed rate coil spring and basic shock absorber combo fitted to their Mustang II front suspension. This style of Mustang II front end used the stock stamped steel control arms. While this worked, it did not allow for ride height adjustment and finding the correct spring rate for your vehicle’s weight was a challenge. Upgrading to a coilover shock system, which provides an easy solution to ride height adjustments, low cost spring rate changes, and better handling, is often the preferred solution.

Retrofitting Mustang 2 front coilovers to the stock Mustang II front suspension can be challenging, as a true coilover shock utilizes a threaded shock body that uses a fixed upper spring seat and an adjustable lower spring seat, eliminating the upper spring pocket on the Mustang II frame or welded component of a Mustang II suspension kit. This design is what gives the coilover shock its ability to easily adjust ride height and swap out spring rates depending upon front vehicle weight and application needs.

To solve this issue, we have created an effective Mustang II coilover shock kit to install Mustang II coilovers that requires no cutting, grinding, or welding and is a true bolt-in to stock or aftermarket Mustang II IFS systems at a great value. This Mustang II coilover shock retrofit will work with both stock stamped lower arms and aftermarket tubular lower control arms (both with and without strut rod systems). These are not universal coilovers that require modification to work on your Mustang II front suspension.

Multiple Spring Rate Options for the Best Ride and Handling

Our Mustang II bolt-in coilover kits are available in both fixed rate shock and single adjustable shock configurations and come with your choice of spring rate. These special springs are wound from premium chrome silicon spring material and available in four spring rates (375, 500, 600, and 700 lb/in rates for various front weights/engine combinations).

We recommend our lightest 375 lb/in springs for vehicles like Model As and Ts, while the 500 and 600 lb/in springs are more suitable for heavier pre-war coupes and sedans. Heavier cars like 60s muscle cars might need to use our 700 lb/in springs depending upon engine size and accessories (AC, power steering, etc.). It is best to weigh your front frame section, engine, and accessories to determine final front suspension weight and choose your spring accordingly.

The springs are tapered so that the upper spring diameter matches the stock Mustang II upper spring seat cup/pocket, yet the bottom of the spring necks down to a standard 2-1/2-inch ID to fit a standard coilover shock dimension, thus allowing a longer spring to fit in place for reduced spring rates and a better ride. Utilizing the factory upper spring pocket also places the spring’s load into the frame, as designed by Ford, versus a single shock mount like most aftermarket coilover conversion shocks, which was not designed to carry the vehicle's front weight and can lead to failure of the upper shock mount in extreme cases. Lastly, the springs are chrome plated to match the coilover shock body and hardware for that show winning appearance.

We offer these Mustang II coilover springs separately for those that make major changes to their hot rod or muscle car, such as switching from a small block to a big block engine, or other changes that would necessitate a spring rate change. So even if you ordered your Mustang II coilover kit with 375 lb/in springs you can quickly and easily upgrade to, say, our 500 lb/in springs to support your engine upgrade’s additional weight.

Works With Most Mustang II Bolt-In Coilover Conversion Shocks

Most of the Mustang II coilover shock conversions use this style of tapered spring to allow using the factory upper spring seat/pocket and a standard 2-1/2-inch coilover shock body. This means our springs will work on Speedway Motors, QA1, and most other brands of Mustang II coilover shock kits that are designed for the stock Mustang II frame’s upper spring seat/pocket. We suggest using our Mustang II upper spring isolators to eliminate metal on metal contact between the spring and the frame pocket that could create squeaks or noise during suspension movement if your original ones are damaged or missing.

At these prices having several different spring rates for different uses is a great option for your Mustang II equipped ride. Want a nice soft ride for that long haul to a big event? You can do that. Then, when you’re going to hit the autocross, you can run a stiffer spring just for that weekend! Changing the springs out takes no time at all, especially if you use one of our coilover spanner wrenches to make quick work of loosening/adjusting the lower spring seat on your coilover shocks.


MFG. Part #
BrandSpeedway Motors
Spring Rate
Spring Rate Range
Free Height8.13"
Material TypeSteel
Progressive Rate SpringNo
Coil Spring End (A)Square
Coil Spring End (B)Square
Inside Diameter Big End
Inside Diameter Small End2.5"
Wire Diameter
Sold in QuantityEach