Wanting to convert a 72 442 rear end over to a posi with gear change as well. Car currently has SA 0070 stamped rear end - according to CSM it's a 2.73 open. I have a posi carrier with the "725" numerals cast in it between the ribs. Is this the correct unit to use in this rear end - and will 3.42 gear & pinion bolt on without having to shim? Thanks!!

 

Yes,the 725 carrier is a 3-series carrier for the 71-up 8.5" 10-bolt.This will take any ratio 2:73 & numerically higher.The 410408N is the more common 3-series carrier for the 8.5" 10-bolt The difference is the 725 has side gears that are NOT machined for c-clips,and the 410408N has side gears that are.Since you are building an 8.5" 10-bolt,for a 71-72 Cutlass/442,you could use either one,since you have bolt-in axles.

 

Thanks Brian - was hoping you'd answer so I can put this to bed. Let me know if you sell a kit for all the seals, bearings (including wheel bearings) to rebuild the rear end - I've read some of you posts on the junk that's out there.

 

You can get all of the Timken bearings & seals at AutoZone,with the exception of the axle bearings,as they stopped carrying those about a year ago.Timken still makes them though.Lately,I have found some suppliers on ebay selling them.

Pinion seal # 2043
pinion bearing,outer # M88048
pinion bearing race,outer # M88010
pinion bearing,inner # M802048
pinion bearing race,inner # M802011
carrier bearing # LM501349 (need 2)
carrier bearing race # LM501314 (need 2)
axle bearing # SET9 other brands call it # A9 (need 2)
axle seal # 712146 (need 2) Do NOT cunfuse this with the thinner #2146

 

Brian, O'Reilly carries the A9 bearing set under the "National" brand name as well as the house brand of Master Pro.

 

Advance Auto also carries the National brand.They are japan or china,don't remember.They will work though.