The '64 to '72 A body rear ends are the only ones that wil bolt in. The '73 and later rear ends will require modifications to make them work. You can put a posi and 3.73 gears in the rear end that you have. The parts are available, but you need to find someone who knows how to set up a ring & pinion set to do the installation. Your car has the 8.2 BOP 10 bolt rear end with a 27 spline pinion and 28 spline bolt in axles. This rear end is stronger than the Chevy 8.2 10 bolt, so don't swap it for the Chevy rear end. A 12 bolt would be stronger, but a good 3.73 posi 12 bolt for a '65 or '66 A body will run you about $1000 to $1700. The '71 and '72 A body 8.5 10 bolt is a good rear end, but a little hard to find. They were used in the Cutlass and Skylark in '71 and '72 only. These may be 1 inch wider than the rear end that is in your car now. They also have bolt in 28 spline axles, but they have a 30 spline pinion.
If you have been doing one wheel burnouts and you put a posi rear end in your car you need to replace the rear tires. If one tire is worn more than the other this will cause the clutches in the posi to slip and get hot while you are driving. It could ruin the posi or possibly ruin the whole rear end because it will cook the oil. The air pressure in the rear tires also must be kept equal.
Last edited by big gear head; 07-25-2012 at 02:17 PM.