Keith Graff

I I have a Camaro 01' Z28 i'm putting a 3.73 gear in it but im not sure which size to get. My buddy tells me there is a tag on the differential letting me know everything about my rear end but I don't see it. It may have fallen off or he's just wrong. I need to know what the diameter of the the gear is. Anyone with the same car or is familiar with my car please let me know what size gear i need before i buy one. Also if anyone has one that's compatible with my car let me know in a message or response and let me know how much you want for it. Thanks!