installed a 12 bolt from a 71 monte carlo and want to make it a posi, will a 3 series carrier work? is there such a thing as a 2 series posi in a 12 bolt chevy? o No:
I have a 2.56 12-bolt posi. The guy who built it for me (Art Houser in PA) made a 3-series carrier work somehow, I don't know enough to tell you how though. Might have involved some sort of custom-made spacer plate or something, I'm not sure. -Bob Cunningham
He must have had to shim the hell out of the passenger side to get it to work. A ring gear spacer will put you in the wrong direction. Each series carrier moves the ring gear over a 1/4".
Might keep an eye out on e-Bay for used 2 series 12 bolt Chevy CAR posi carriers. Beware, that many 12 bolt carriers on e-Bay are '71-76 MP series carriers, so ask for the EDB casting number, feel free & post it here, if you can't ID. Usually, one can get into a used 12 bolt Chevy 2 series posi carrier for under a $150. For typical cruiser car type r/e build, such a carrier will often be fine. Do keep in mind, if your Buick has a ton of torque, & the car is putting it to the ground, the 10-18 spider/side gears in the oem Eaton 2 & & most 3 series) posis are very weak. For strong performance build, they need to be replaced with stronger versions. :3gears: Roger
