Found it :-) here you can read
http://www.mustangandfords.com/techa.../138_0309_vip/
This is the intresting bit
"Tremec then offered the T56 six-speed in several GM platforms and eventually the Dodge Viper. Unfortunately, there was no easy way to get this stout transmission and its much-sought-after extra Overdrive gear into a Mustang.
Eventually, Tremec came out with Ford T56 aftermarket applications. Even the '03 Cobra bangs gears in a T56. But these models are rated at roughly 450 lb-ft of torque. This is much more than the T5 (300), the T45 (325), or even the Tremec 3550 (350-425 lb-ft depending upon model). The only other bolt-in transmission rated higher is the Tremec 3550 TKO II at 475, but it has one less gear and Fifth is a higher 0.82 ratio versus the regular 0.68.
For those who need even more torque capacity, D&D Performance--long a group of wizards in the ways of the manual transmission and clutch--began working on retrofitting a Viper-based T56 into the Mustang. The Viper's higher rating of 550 lb-ft means more strength behind the high-end street cars putting out 700 or more horsepower. And, with the Viper T56 you not only get the coveted extra gear, but also Sixth gear is a low 0.50 ratio versus the Ford T56's 0.62. After taking apart a T56, D&D "blueprints" it with the latest upgrades, including a steel 3-4 shift fork, carbon-fiber blocker rings on all gears (except Reverse, which still has brass), and verifying clearances and other minor details to ensure strength. The folks at D&D tell us in the five years they've been selling the Viper-spec trans to owners with "certifiably crazy power levels," they've never had a report of breakage."
Linear Mode
