It seems that if you own a GM musclecar, you must have a 12-bolt differential residing under the rear framerails. Nearly every nontubbed GM car that we feature proudly boasts a 12-bolt posi among the ...

Thanks to auburn gear, the chew 3-series 12-bolt posi is back! Chevy's beefy 12-bolt differential has always been the rearend of choice among Bow-Tie musclecar enthusiasts. Unfortunately, in recent ...