T-56 viper box behind 545 cobra

[ByronRACE]

IMHO, I'd run the Viper T56 (i.e. with the Viper input shaft) and you should be just fine. If you want to go crazy, use one of the newer "Tranzilla" or "G-Force" gear set models.

I have a Viper T56 behind mine and it makes well over 800/800. I shut it down on the dynojet 248 at 760/760 at 5500rpm having just barely reached peak torque. That was about 1400mi ago when the engine had about 100mi on it and no damage yet, and I've visited 7K regularly. According to the logger, it's at the limit of 83lb/hr injectors at 7000rpm, so that's a lot at the rear wheels. And, that's with a *stock* viper trans, and 3.50 rear gears with 335 road race compound on the rear which does not slip in 3rd on up...so that transmission can handle some real torque. There's a lot of viper guys out there making 700-1200hp through these transmissions.

On the other hand, I've seen the ford-splined T56 break at less power. A friend sheared the input shaft off his in a blown 408 Mustang making 700rwhp or so. He was in 4th gear at WOT when it happened. I've seen another one in a lightning pickup snap the input shaft on a 1-2 shift. So far, I've never seen the viper input shaft fail.

Byron