[Zspoiler]

I would rebuild yours .The reason why GM quit building the 12 bolt is because it is just as strong. My car is a 1979 Z-28 RS Camaro. It has a supercharged small block Chevy with a Super T-10 4 speed. The speedometer has turned over 6 times before I rebuilt the 10 bolt.I upgraded to the Moroso "Brute Strength" carrier for a 10 bolt. It has heavier springs and clutches than stock. Stock GM 3:42 ring and pinion.And Mosier 31 Spline axels. But I tend to over build stuff when upgrade the car .Because of the amount of power the engine is capable of making . So if the is going to be fairly stock. I would rebuild it stock but add a positraction carrier to it. And if want to have a lot healthier engine down the road. I do the upgrades like I did. I like to do things only once. Especially big ticket items like differentials. I all depends on you and your pocket book. Good Luck to you.