I have a friend that works at ford and he is telling me that my 01 cobra isnt just gears I have to change something bigger I dont remember exactly what he said but can you guys tell me about this?
What was that again, "isn't just gears?" Sort of confusing...
I can only guess as to what your friend at Ford was trying to convey.
Perhaps he was trying to let you know that you will need some kind of speedo calibration after installing new gears so that the odometer is still in "sync" (either via a speed cal device or via a chip).
It's in your best interest to calibrate for the change in gears so your mileage is accurately reflected on the dash.
Most tuners/chips will tahe care of the ratio difference and give you more HP at the same time. When you change the gears, change the differential bushings to aluminum.
Yes, the rear axle is what houses the "gear". Stock is a 3.27 gear. The gear acts as a torque multiplier to spin the rear wheels. Since you have a 3.27 gear now, the driveshaft has to turn 3.27 times to spin the wheels once. Most people upgrade to a 4.10 or 4.30 gear to accelerate faster. If you install a 4.10 gear the driveshaft will spin 4.10 times to spin the wheels once. While this would make it seem like you are having the motor work harder to spin the wheels that same 1 time over, you are getting to the upper RPM's faster which is where our cars make power....in the upper RPM range.
Since your car has an Independent Rear Suspension it won't be that cheap. A lot of people will do a 4.10 gear swap, aluminum driveshaft (since it's spinning faster now the aluminum shaft basically eliminates vibration), and computer chip to match the speedomoter (since MPH is calculated by variables that you will change with the gear change).