Mustang S550 (2015+) 9″ IRS Kit


SKU: FOR10904A Category:


The GForce Engineering fully-fabricated 9” IRS for the 2015-2016 S550 Mustang is a complete bolt-in independent rear suspension that replaces your drive-line from the transmission back. Includes a fabricated 9” housing that bolts to the stock differential mounting points. It also includes GForce bullet-proof Outlaw axles, 35-spline inner stubs, new outer stubs and the option for your choice of driveshafts.

Its no secret that stock IRS components can be a real weak point in these cars. Once power levels exceed the limitations of the stock diff, upgraded axles may hold up, but they expose the weak points in the differential. This is where the GForce 9” becomes a necessary upgrade.

The bolt-in 9” kit eliminates the flex, noise, “clunking” and weak points of the OEM rear. Plus, you have the confidence knowing you are putting your power through a race-proven bulletproof rear end, but you get all the benefits and advantages an IRS can provide. In addition, the GForce 9” kit comes standard with 35 spline inner stubs. In fact it is the only 9” IRS on the market with the beefy 35-Spline inner axle stubs.

The GForce 9” has been proven to support 2000+ in “real-world” applications. The GForce 9” kit holds IRS records in the ¼ mile, standing mile and 2-mile in wheel standing IRS vehicles. It’s safe the say the misconception that you cannot put power through an IRS and make it live has been officially debunked.

All GForce Engineering 9” housings are laser cut, bent on a CNC press brake and tig welded for flawless finish and unmatched strength. 9” kits can be purchased as a complete kit with pumpkin and driveshaft. Our preferred provider is Strange Engineering. GForce can also make you driveshafts specifically designed to work with the 9” replacement rear and most common transmission options. If you are looking for something other than the options provided here. Please call out tech lines at (316) 260-8433

More about GForce Engineering Outlaw Axles
GForce Engineering Outlaw axles are CNC machined from aerospace billet alloy. The proprietary material has been closely compared to the popular 300m alloy. In both our testing and in third party testing, we have found our alloy to have a higher tensile strength making it a stronger axle than comparable 300m axles. In addition, these axles are engineered to absorb the “shock” of a hard launch.

The real strength of the GForce Outlaw axles comes from the billet, CNC machined CV internals. Traditional CV’s in this size would use 28-spline axles and “CV stars”. In this case, GForce machines billet 31 spline stars and 31 spline axles. This provides tighter tolerances and less wear as well as additional strength from premium materials and more spline engagement.

GForce 9” Kits Include the following:

Fabricated 9” housing (bolts to factory locations)
Heavy-duty front mount
Solid aluminum or poly bushings
35 Spline Inner and Outer Stubs
Outlaw 9” axles
All necessary hardware
Third member to housing
Housing and front mount to cradle
Your choice of third member: Pro-Iron or HD aluminum (Strange)
Your choice of driveshaft: 3.5” aluminum or 4” aluminum

Note: If you are interested in 31 spline diffs, the GForce 9” can be ordered with 31-spline inner stubs. Please call for more information on this application.

Carbon Fiber driveshafts are available for trans swap applications. Must use a transmission with a slip yoke.

GForce backs all their Outlaw Axles and 9” kits with a lifetime warranty. Warranty is limited to the parts GForce Manufactures and is non-transferrable. For more details on the warranty, visit us here:

Additional information

Weight 145 lbs
Dimensions 48 × 12 × 24 in


There are no reviews yet.

Be the first to review “Mustang S550 (2015+) 9″ IRS Kit”