[Jim Moshier]

I have a 1971 Grand Prix with a what I have thought was a chevy 12 bolt rearend 3.07. Is that a chevy or a pontiac and is it a 2 or 3 series carrier. The numbers on the right axle tube are WT and according to Wallaceracing,

1971 GP 3.07 12 bolt 43/14 teeth count WT

I'm looking to get a posi unit and will need to know which carrier series it is.

Jim

['ol Pinion head]

The rear is a McKinnon plant built 12 bolt. Posi carrier can be any 3 series (3.07-3.73) 12 bolt Chebbie car style carrier. The original pinion seal used with the factory 3R flange is different than the normal 12 bolt Chebby pinion seal. Factory McKinnon use axles are slightly more HD than std 12 bolt Chebby axles, but smart idea to replace with a pair of Mosers. One thing have to be very careful with is factory 3R pinion flange, they can chip out on the outside corners of where the u-bolts bolt gon through during a differential build if not careful. Tearing down all the way, installing new gearset/pinion bearings, it's very smart to use a common & easy to source Chebby 1310 pinion flange when compressing the crush sleeve. Right before the crushsleeve is propperrly crushed/ pinion drag is close to spec, remove the Chebby 1310 pinion flange, and with 4 bolts tightened well through pinion flange holding tool, sneak up on drag.

[Jim Moshier]

Great info Pinionhead I thought I was going to go the whole carrier gears and rebuild. Now I hade options!! Cool