Where on the vin would I found out the axle ratio for my car?

It's not on the VIN. There is an option code sticker, located in or under the center console glove box that shows how the car was built. Here are some codes I found, but I don't know if all apply to the 1989. GH0 - 3.54 Rear Axle Ratio GM1 - 2.59 Rear Axle Ratio GU2 - 2.73 Rear Axle Ratio GW4 - 3.31 Rear Axle Ratio G44 - 3.07 Rear Axle Ratio

i have a 1978 corvette pace car , automatic trans , how do I find the rear end gear ratio, ,based on vin # or rpo code ????