Side by side, we noticed that the thinnest part is within the splines where the inner diameter of the splined area is much smaller on the 10-spline unit. This is where many people have snapped shafts, even at lower power levels like ours (gee, who'da thunk that 453 rwhp would ever be considered a lower power level?). Going to a 26-spline input shaft is a highly recommended upgrade no matter how modified or unmodified your Cobra may be. We recommend having a qualified transmission shop swap the shaft for you, as getting into the inner workings of a transmission may be a bit daunting for the first-timer. If you're a hands-on kinda guy, it would be ideal to have a buddy that is familiar with T56s get involved, as he'll probably get dirty for a beer and a sandwich (much like us). Keep in mind that you'll need to order a clutch disc to match the 26-spline shaft.
With our Cobra put back together, we added four quarts of Royal Purple Synchromax synthetic transmission fluid and were rewarded with silky-smooth clutch action and tenacious bite. The best part of this upgrade was the increase in driveability and comfort. Pedal effort with the Spec Super Twin is literally half of what it used to be with the stock Cobra clutch. It makes the car a true pleasure to drive, and being stuck in traffic no longer makes us feel like we're training for a powerlifting championship.
Follow along as we swap out the clutch and input shaft in our own garage. With some free time and savvy wrench turning, you can also get some more bite from your Cobra's clutch.
With the transmission back...
With the transmission back together, we decided to mock up the new Spec clutch. Here, we slide on the two clutch discs and the floater plate to see how things fit. It's important to note that some aftermarket input shafts have splined sections that don't run the full length they're supposed to. That's bad because the forward disc in a twin-disc setup will have only a portion of its splines engaged onto the input shaft. To make sure you get the right one, ask whomever you buy your input shaft from if it has a full-length snout for use with a twin disc clutch. As you can see here, we have full and proper spline engagement.
With the new input shaft in...
With the new input shaft in place, we cleaned off the mounting flanges on the case and front cover, and applied a bead of silicone sealant. A cool thing to note is that Cobras come with a steel 3-4 shift fork from the factory, not aluminum like on some GM cars, which are prone to cracking. With the cover back on, we tightened the factory bolts to the factory-recommended 26 ft-lb.
Once back underneath, we removed...
Once back underneath, we removed the transmission wiring harness and unbolted the clutch housing with a 13mm socket and an assortment of swivels. The starter must also be undone, so don't forget to disconnect your battery.
The factory flywheel is aluminum...
The factory flywheel is aluminum with a nonreplaceable steel insert. With a 17mm socket, the eight factory flywheel bolts come right off. We then removed the pilot bearing from the crank and installed the new one that was provided with the clutch kit.
The Spec flywheel, also an...
The Spec flywheel, also an aluminum piece, bolts right into place. Positioning is critical, but luckily for all of us, the bolt-hole pattern will only line up with the crankshaft in one position. Reusing the stock steel bolt plate, we hold the flywheel in place with the proper tool and tighten the bolts to 60 ft-lb.
Adding some fresh grease onto...
Adding some fresh grease onto the clutch fork's pivot, we slid the included release bearing into place.
With the alignment tool in...
With the alignment tool in place, we slowly snugged the clutch cover bolts, making sure the installation tool would still glide smoothly in and out. The cover bolts were then torqued to a final 30 ft-lb.
With our tranny ready to go...
With our tranny ready to go back in, we took the advice of a friend and tried out his favorite shifter combination, which consists of a Pro-5.0 base with a Steeda Tri-Ax handle and shift knob. It turned out nice, giving the perfect combination of tight throws with ideal knob placement.
When all was said and done,...
When all was said and done, we filled the unit with four quarts of Royal Purple Synchromax manual transmission fluid, designed for manual transmissions that would normally use automatic transmission fluid (ATF).