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.