Twin clutch installation in a 2011 Mustang

Sometimes adding performance means being able to contain it

Ricardo Topete - August 01, 2011 09:00 AM


For Your Information:



(888) 447-6487



(714) 630-2764



(972) 602-9484


1 Pretty in Red. McLeod’s Street Twin clutch kit is available with either a billet steel or billet aluminum flywheel, and comes with all necessary hardware required for assembly. Our tester received the billet aluminum option (part number 63308-00-02).


2 Lee Kilcoyne, of McLeod, came by to lend a hand with the project. He begins by removing the exhaust system. Yes, Lee always smiles while he works!


3 As with any clutch job, the starter is unbolted from the bellhousing and set off to the side. Then, Lee gets help from GTR’s lead technician, Chris Balster, who is armed with a transmission jack. Together they separate the six-speed manual transmission, once all the bolts are removed and all the electrical connectors are unplugged. Kilcoyne straps the transmission with a ratchet tie-down for safety. Do-it-yourselfers working on jackstands and laying on their backs will want to enlist a friend or two for this step. Drop the transmission and it can really ruin your day. New for 2011 is the 23-spline input shaft.


4 All 5.0L Coyote motors have an eight-bolt, zero-balance, 164-tooth flywheel. Our Street Twin includes a new billet aluminum flywheel, so there is no need to have it resurfaced, as is normally done when replacing a clutch.


5 For 2011, Ford moved the crank trigger wheel to the back of the crankshaft. It now sits between the crankshaft and the flywheel. According to Ford, this greatly increases timing consistency, which is critical at 7,000-plus rpm.


6 The Street Twin comes assembled in the same order that it must be installed onto the vehicle. This partially disassembled view gives you an idea of the precise engineering required to make this system work. Be sure to align the blue paint markings during the installation process to ensure precise balancing.


7 The entire Street Twin assembly tips the scales at 38 pounds, which is a full 10 pounds lighter than the factory clutch/flywheel combination. Cutting weight is always a plus, but more importantly, we are reducing rotational mass. Put simply, less power is consumed in rotating the lighter Street Twin, which is power that ultimately makes its way to the rear wheels.


8 Lee installs the Street Twin’s billet aluminum flywheel with a custom 23-spline clutch alignment tool he fabricated. All future 2011 Street Twin kits will include an alignment tool similar to this, as it is necessary for installation. The Street Twin pressure plate is torqued down, after which the clutch alignment tool can be removed.


9 Installation of the transmission is straightforward. The only tricky part is getting to the upper bellhousing bolts. The only way to access them is with a tree-foot extension with a swivel socket on the end.


10 Before disassembly, Chris marked the driveshaft’s position relative to the axle housing to ensure proper alignment. This eliminates the risk of driveline vibrations associated with it being out-of-balance.


11 Lastly, the exhaust system is reconnected. At this point, as tempting as it would be to do a Funny Car-style burnout, we can begin the recommended 500-mile break-in procedure. Best results are achieved with normal street stop-and-go driving. The objective is to gradually and properly seat the discs with the pressure plate and flywheel.

Image 1 of 12

“Street Twin is to provide high-powered muscle cars with a street-friendly clutch kit that can handle over 1,200 hp”

2011 Mustang GT owners are a lucky bunch. They can easily achieve “street-legend” status by eclipsing the 500 rwhp mark with nothing more than a supercharger. The 5.0L Coyote motor that is standard issue on the 2011 makes nearly 400 hp to the rear wheels in stock form!

Of course, with this type of power comes the need to harness it. This month we will take a close look at upgrading the stock clutch to a unit that can tame even the baddest ’Stang.

Our test subject is a stock 2011 5.0-powered GT belonging to Dan Oliver of Outperformance Shop. Big boost and big power are in this pony’s future, so Dan started shopping for a performance clutch system that would stand up to 500-plus rwhp and still offer street-friendly driving manners. Sounds like a tall order, right? A clutch that has race car levels of holding power and can be used as a daily driver. The solution: McLeod’s Street Twin clutch system.

The premise behind the McLeod Street Twin is to provide high-powered muscle cars with a street-friendly clutch kit that can handle over 1,200 hp (yes, 1,200). The use of organic-lined clutch discs ensures smooth clutch engagement and operation without any annoying clutch chatter. Furthermore, the use of two clutch discs effectively doubles the surface area of the clutch discs and yields extreme clamping power while still maintaining a very soft pedal effort. In short, McLeod’s Street Twin clutch kit for the 2011 5.0 Mustang offers the best of both worlds: unbeatable performance and civilized street manners.

McLeod offers their Street Twin in a few different configurations. We received part number 6338-00-02, which includes McLeod’s billet aluminum flywheel and organic-lined clutches, which are rated to 1,200hp. Our Street Twin assembly was a full 10 pounds lighter than the stock clutch/flywheel it replaced. The Street Twin is also available with a billet steel flywheel. Insanely powered Mustangs can even opt for the Street Twin with ceramic-lined clutch discs, which are rated to 1,800hp!

For this project, we visited the Mustang gurus at GTR High Performance (Rancho Cucamonga, California), which is an authorized McLeod dealer and installation center. GTR’s staff got a helping hand from Lee Kilcoyne of McLeod, who made the trip out to assist with the project. In several hours, the Mustang was Street Twin-equipped and ready to go. Do-it-yourselfers will want to allow considerably more time for a job of this magnitude. Although this project can be done at home, you will want to enlist a friend to provide help and moral support. Follow along as GTR and McLeod fortify Outperformance’s Mustang with a killer clutch kit that will stand up to the supercharger that is in its future.