how much RWHP is safe on a '03 six speed trans ?

68 & 00 GT

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May 14, 2003
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arrr. Obviously I meant 03 Cobra six speed -

first off would it help, or hinder my 1/4 times vs. my 5 speed ?
what about highway racing ?

I have 373's would it give me top speed, and better gas mileage ?

OK now how much RWHP can they handle. My goal is to be 650 RWHP by early next year. Wonder if it's a good investment or not -

thanks
 
Stock application I would say it will hurt you because they are much steeper gears. You may want to lower your rearend gears. As far as how much it can hold, I am pretty sure that they are rated at 500rwhp, but I have seen cars with close to 700 holding up fine. How long it will last i am not sure, but it is much better that the 3650 :nonono: I would think that it would help with both top speed and gas mileage because of the extra overdrive that you have. I hope this helps.
 
The real answer is subjective. If you have 650 hp and hook it with slicks at the dragstrip, you could break. If you're running street tires, you'll never hook enough to break it. You'd lose traction first. If you drive like Capt Caveman you could break an iron anvil. If you just do spirited driving you'd be fine and it'd be fine upgrade at any time.
 
If the 6 speed is the T-56 that comes in F-Body's, you are pushing the envelope at 5-550 rwhp. I suppose if you are putting out tons of tourque, and less hp, the prognosis would be the same. As far as the T-56, there aren't any companies that make one to withstand much more than 650hp (replaced with billet internals). Most will go to an automatic after that. Again, this is what i know from my Camaro and T/A buddies with 600+ hp six speed cars.
 
they have a torque rating of 450lb's.

In reality it is more a function of traction. it is the intial shock you give it that breaks it most of the time. I takes lost of traction to put 450lbs to the pavement and not spin the tires.
 
With a Spec stage 3-4 clutch I think they've been good for well over 500, sometimes 600 RWHP......

If you can drive it like you stole it, and looking at the fact that you hve more room to mod with the different ratios, you should be quicker..... With that kinda power you should still be able to keep it in 4th, which would make for some better times, and the extra gears would give you MUCH better MPG's, and (though I don't condone it) will give you better top end with the power to keep pulling.

If you get the extra gear, get some 3.90's or 4.10's ;)

-Will
 
GoBabyVroommm said:
There is a viper t-56 that we can get to for our mustangs it can hold a lot of hp. Not sure how much but if your interested in a six speed i would look into it.


The cobra one is the same exact tranny, just different input and output shafts... and steeper first gear.

Your car will probably gain a bit of time down the track, because you will be in your upper powerband for longer because you have an extra gear ( 5 vs 4 ) that are for racing
 
White360RFnSwee said:
The cobra one is the same exact tranny, just different input and output shafts... and steeper first gear.

Your car will probably gain a bit of time down the track, because you will be in your upper powerband for longer because you have an extra gear ( 5 vs 4 ) that are for racing


What about the 00 R t-56 i don't know if its really strong but i heard it has some nice gear ratios. The R trans is different than the 03/04 t-56 right????
 
White360RFnSwee said:
Your car will probably gain a bit of time down the track
~how much time added ?

I mean my car will be pretty much full weight always other than new seats ( I mainly want to get soon so I can put my leather seats in my 68). I just want raw horses, and traction to push me along with very seldom track time.