How bad is it too...

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my 5th tops out at 153 mph. and it still pulls hard in 6th, but i didnt wanna go too much more than that so i just let off.

I shift mine everyday at 6300-6400. It pulls strong to 6200, then the extra couple 100 RPM over the 6200 set up the next gear to be deeper into the power curve. I have the rev limiter set at exactly 6400. I have hit the revlimiter pretty hard before at the top of 2nd gear and tagged a few plugs with the piston, but nothing ever got hurt. I even looked into the cylinder with a bore scope and there was just a TINY little mark on the top of the piston.

Over 5k RPM's, my stock tach reads about 300 RPM higher than my Autometer. I know my Autometer is more accurate because I can hit recall on it after hitting the limiter and it shows exactly 6400.

As long as you let off as soon as you hit the limiter, you will normally be fine.



i'm guessing he is still on the stock trans. with the t56 you can pull hard since it has a better gear ratio than your 5th OD in the stock trans
 
My auto shifts at past 6k every time I go WOT - i.e. ALL THE TIME. I'm not worried. Ford put the limiter where it is for a reason. They know some people are going to beat the living crap out of their cars (esp rentals!!:D ), and must surely set it at point they think is ok so that they avoid warranty claims.
 
My auto shifts at past 6k every time I go WOT - i.e. ALL THE TIME. I'm not worried. Ford put the limiter where it is for a reason. They know some people are going to beat the living crap out of their cars (esp rentals!!:D ), and must surely set it at point they think is ok so that they avoid warranty claims.

Can you even hit the limiter in an auto?
 
Do you have a T-56? Are you saying that when you shift from 4th at 6350 RPM's, your RPM's go down to 3500 in 5th?



I don't know what year he has, but in 2003-2004, ford changed 5th gear in the T-3650 to equal the 6th gear in the T-56...so it would be a 1:1 to 0.63 jump (the Cobra has a 0.8X ratio in between) Shifting from 4th to 5th in a Gt/Mach 1 would be the equivalent of shifting from 4th gear to 6th gear when driving an '03/04 cobra.

SO when i'm in 4th gear at 3000RPM, and shift to 5th, the RPM's drop down to around 1500RPM....which doesn't leave a whole hell of a lot of power for rolling on the throttle to pass a car. I ususually just leave it in 4th then.
 
cool thanks guys, yea i noticed that the stock tachometer says im idling right at around 900 but when my friend hooked up his scanner it said i was only idling at 750, nice to know im not hurting anything, guess my next "mod" will be a tach id like to have that extra accuracy

Your guage has problems.
 
I don't know what year he has, but in 2003-2004, ford changed 5th gear in the T-3650 to equal the 6th gear in the T-56...so it would be a 1:1 to 0.63 jump (the Cobra has a 0.8X ratio in between) Shifting from 4th to 5th in a Gt/Mach 1 would be the equivalent of shifting from 4th gear to 6th gear when driving an '03/04 cobra.

SO when i'm in 4th gear at 3000RPM, and shift to 5th, the RPM's drop down to around 1500RPM....which doesn't leave a whole hell of a lot of power for rolling on the throttle to pass a car. I ususually just leave it in 4th then.

I understand what you're trying say, but his RPM difference (drop) was just a little overstated by about 500 RPM. No big deal, but the stock tach can be off by as much 300-350 RPM as well. The .62 5th gear on the 3650 is good for guys that go with alot of gear, but I agree it's really soft for people with 3.73's or less.