Chevy 12 bolt rear end. 2:73 posi. Just came out of 1970 Chevelle. Casting #3969278. CH code stamp for 71 -72 Chevelle. Fits 68 to 72 Chevelle and Monte Carlo. 54 1/2" inside backing plate to backing plate. Comes with brakes(good condition), emergency cables, hydraulic hose and u-joint. Excellent condition. $1600.00 firm.