Only 1,566 1992 corvettes produced with G87 code. What does this mean? What code did the other 1992 corvettes have for the rear end? Thanks

G87 would be the speedometer gear ratio. There were 5 different rear end gear ratios available, I think, and the 2.73 was probably the "standard/base" ratio. Automatics cars had different standard ratios than the manual cars. With different rear gear ratios, the speedo adapter/housing would have to be correct to match the diameter/tooth count of the gear itself, so the G87 simply means the car has an optional rear end gear ratio that required a different speedo adapter.
For instance, my '85 also has G87 listed on the RPO service label, and it has a 3.07 rear gear ratio.
hth
Adams' Apple2011-01-11 10:54:28

Thanks Joel

I came across this info right after I bought the '85. The speedo housing/connector was leaking. I called the dealer to get a new one, and that's where I learned about the different housing/adapters for the different ratios. Even tho the speedo is still gear driven, the electrical adapter/housing has to be matched(calibrated) with the rear ratio. The adapters will work within a small window of different rear gear ratios and still calibrate correctly. Installing the wrong adaptor/housing would throw the speedo off, even using the same speedo gears.

What is the gear ratio code for the rear end? Do you think mine is 3.07 too? Thanks

You'll need to look on your RPO label and see. The label is usually on the inside of one of the storage compartment doors in the back...you're looking for any "G" codes.

GM3  3.45 ratio. Thanks Joel