Hi, I need help. I have a 67 Bird project 400 4speed with a 10 bolt. I pulled the cover tonight to figure out the gear ratio and found it to be a 4.33/1. The numbers on the ring gear are: 39 9 GM 1 67 JA The ratio is 39 divide by 9= 4.33. I believe the 1 67 is the date code. How can I tell if this is original and correct for the car?
