What transmission are yall running when you get up to around 500-600 horsepower? Does the T-56 handle all that power? I see its only rated to 450 lb-ft, and I always hear of cobras pushing much more than that, but never hear of any tranny swaps.
I use the Tremec TKO600. It is rated @ 600 ft/lb. I am barely pushing half that amount of torque right now, but I never have to worry about exceeding my tranny down the road. Did the 03/04 Cobra's come with a Viper Spec T56? I doubt it if they are only rated @ 450. Check out Tremec's website, and give them a call. They have GREAT customer service!
I was looking at the TKO600 and the T56 gear ratio's. Did you notice a big difference when you put the TKO in? Did you put the 4.10's in before or after the tranny swap?
The stock T56 in the 03/04 is not a Viper spec setup and is only factory rated at 450 torque. The weak link in the stock tranny is the input shaft. Ford decided to go with a 10-spline. Many owners will have it upgraded with a 26-spline input shaft from Liberty gears. This takes the torque rating to over 500.
After the 26-spine upgrade you don't hear of many failures at all. The weak links move to the half-shafts and the clutch after that.
I am running a used D&D T56, was told it was a VIPER version, it is 4-5 years old. I question it if is a VIPER since it has 10 Spline Input shaft. Was told back then they had 10s. Anyway.....
I agree with Meat, 26 spline is the way to go for this power level and now my weak link. I am pushing 570ish to the rear. I have a solid axle so no 1/2 shaft worries here. You got a GT so no issue for you.
I will say I broke more 1/2 shafts at 450-560RWHP than I did T45s. T45 hung in there pretty good. She was still solid when I did the swap and sold her, but she was my 2nd T45 tranny.