I have a 10 bolt rear differential from a 1966 Chevelle. It has 3.36 gear ratio, 5 bolt (5x4 - 3/4 bolt pattern), wheel studs are 7/16"x 20. It runs well but does have a small oil leak near the pinion yolk. Listed for $1, but would appreciate it if you paid what you felt it was worth. I upgraded to a Ford 9" and no longer need it, just trying to help another old GM car person out. Item is located in Cottonwood Heights near Brighton High School and is outside to grab anytime.