hi, i was wondering what gear ratio my 89 K5 blazer has, i believe it to be a 373 ratio, i have all codes off the glovebox and it includes a GT4 number on it??, any help is appreciated

 

Yes you are correct you that rpo code indicates you have a 3.73 rear gear ratio, if you ever wonder what other options your vehicle is equipped with, just search "GM RPO code lookup" and go through, 1 by 1 your rpo codes in the glovebox.
And btw, welcome to the forum.

 

thank you. i appreciate it!!

 

Axle Charts

 

thank you for the charts