Re: 3.73 gears
you have a live rear axle under the back of you car. If you go lay down behind the car in front of the gas tank where the wheels bolt to you will see the rear end it goes all the way across and has a Pumpking round shaped thing in the middle between the tires, the drive shaft bolts to the other side of this, the drive shaft comes from the transmission.
The pumpkin holds the rear end gears, the drive shaft turns the rear end gears and then the axles are turned by the differential which the gears are attatched to. If you have a locking differential both wheels will turn, if not one wheel will turn (if its up in the air on wheel will turn one way and the other the other way) your car stock does not have a locking differenatial.
your stock rear end is a 7.5 inch (measured by the size of the pumpkin i belive) and an 8.8 is the SAME rear end with a larger pumpking and larger rear end gears, thus its stronger.
Your stock gear ratio is 3.27, that the drive shafts turning around one full time compared to the wheels turnning around one full time, thats where those numbers come from. One full turn of the wheels equals 3.27, in your case, rotations of the drive shaft.
I would HIGHLY recommend buying a complete 8.8 rear end and having it PROFESIONALY built with 3.73 or 4.10 ratio gears and a rebuilt differential unit (they have locking units stock) then just bolt it up and keep your 7.5 as spare or sell it for a couple hundred bucks~ The axle shats in either rear end are the same (8.8 rear ends from 99 up mustangs will work in 99 up cars, the 99 up 8.8s are longer than the previous years)
2003 Cobra Vert (Redfire) #3938 of 5082 @ 05/27/2003
472rwhp/493rwtq -Modification List
- Dyno Sheet
2012 Mustang 3.7L M6 (Kona Blue)
2011 Ford Edge Sport (Red Metallic)