Could i replace my 5 speed transmission for a 6 speed in my 03 Mustang GT?

 

yes!

http://www.ddperformance.com/T56%20Kits.htm

 

yes

 

Would a Cobra 6-speed swap in ?

 

and again. Yes.

 

Not to Hi Jack this thread but I was considering the same thing, could anyone give the PROS and CONS of swapping to a 6 Speed vs keeping the 5

 

one pro is the lower final gear for better highway fuel economy, but most 6-speeds are heavier so theres a con

 

The benefit of the 6 speed is the close ratio gears. However, the 5-speed is lighter and doesn't have a disadvantage over mileage (.68 vs .62 final gears). Also, depending on where the T56 came from, 1st gear could be as low as 2.66 but 5 speeds have a 1st gear of 3.38. So, what it boils down to is a road racer benefits from the close ratios of the T56 while a drag racer benefits from the steep 1st gear and light weight of the 5 speeds. Personally, I'd stick w/ a 5 speed. Another option to look at also is the Richmond 6 speed which has 5 close ratio gears and 1 overdrive gear.

 

Thanks for the reply, good information

 

A few more pros:

*The T56 is way stronger than the TR3650 that comes in most new edge mustangs.

*The T56 is quieter than the 5 speeds.

*The T56 is more well made and doesn't have as finicky of a shifting mechanism as the 5 speed.

 

You could also consider the viper spec t56 or z06 spec t56. I dont recall the ratios of those but I know first gear is fairly long in the new z06s.. its probably 3.36. Its also in the aston martin vanquish and db7, holden comadore, ect...

 

Can't use the T56 from Corvettes since they are transaxles.