in a prior thread i was told that i should be able to run at 95 or so still in third, tried that, not a good idea. 85 in the red for me, 4th, 105 in the red, is that stock gearing? thanks for the info guys, your upmost knowledge astounds me!!

 

The best way to tell is to take off the rear diff cover with car in neutral and wheels in the air and count the number of teeth on the ring/number of teeth on the pinion. This will give you the exact gear ratio. This is if it is not stamped on the gears, most of the time, the ratio is stamped on the gears. I would also try a shift light and shift at 5600 RPM. The stock tach tends to be a little off when it is spinning up quickly.

With the #'s you gave, 85mph at 5600 RPM 4th is 3.86 gear and 105 at 5600 RPM 4th is 4.07. This leads me to believe that you may either be shifting early, or possibly have 4.10's. Like I said, the best way to make sure is to pull the diff cover and count the teeth. BTW 4.10's have 41 ring/10 pinion teeth.

 

You could also raise the rear up and have someone rotate the a tyre count the rotations the drive shaft makes and divide it by the number of rotation of the tyre.
If the rpm and speedo are calibrated correct, it seems that you have somthing like 4.56.

 

For reference, I have stock gears in my m6 also. A couple years ago, the way my car was set up, I would manage to just barely hit the rev limiter in 3rd crossing the finish line. This was with my rev limiter raised to 6,200 rpm. My fastest trap speed was 104 mph, but usually 103.

 

well, there goes the idea of buying 3:73's. seems i already have something similar, cause im definitly not gonna pull 100 in third! im thinking that the previous owner already installed a set. easy way to guage, is the gearing the same as an ls1 with the m6, should i be able to pull 75 in second stock on the lt1?

 

LS1's have the same gearing as LT1's in the rear.

 

how about in the tranny, my sisters 00' ls1 will pull 75 in second, 105 or so in third, if i had the stock ratio in the rear, is this what i should be pulling? 55 in second and im about bouncing of the limiter, does it sound like i have stock gears? thanks for all the help.

 

All the 94-02 manual transmissions have the same gearing as do the rear ends. The ls1 will actually go a few mph faster in each gear because it redlines at 6000 as opposed to 5700. However if you were to run the lt1 to 6000 they would both be traveling the same speed.

 

Its actually like 6200 for the ls1 and 5850 for the lt1. You should be able to go about 95-98 in third before you hit the limiter with a stock tire. If you are doing less than that you probably have gears.

Btw, do not pull the cover off to count that teeth. That would be a complete waste of time. Jack the car in the air and put a mark on the ds. With one complete tire rotation count the number of times that the ds spins.

 

perfect!!! saved me some money on gears!!!! 3:73 gears according the quick way (rotating tires while watching driveshaft, almost 4 times for 1 tire rotation.) that is a best guess. thanks guys

 

I was referring to what the redline is not what the rev limiter is set at.