GM passenger car 12-bolt 8.875" ring gear diameter, 5.14 ratio, pinion depth is 2.861". This matched set only has 1 mile on it (4-runs on it in a 12-bolt 66' Chevelle). One of the ring gear's teeth is slightly machined down so the cross shaft retaining bolt can be inserted (strange's recommendation, in the photo). It has been in the original box, in a heated shop for the past 25 years. I am the original owner. Does not come with an installation kit. Cash only. This matched set ratio, is expensive today!