how can i find out what gearing i have?

You most likely have 2.73's or possibly 3.08's. You can check by jacking up the rear of the car, putting a mark on the driveshaft,spin the rear tires, and count the number of times the tire spins in relation to one driveshaft rotation. If its about 2 and 3/4 times, you have 2.73, if its a little more than 3 times, you have 3.08's.