Technical NEED HELP IDENTIFYING REAR END (NOT MINE)

First time post here! You guys are an AMAZING resource!

I recently acquired a 1962 Chevy II Gasser. It looks like it was built in the 60s or 70s and needs A LOT of work before it goes down the track. I just started digging into it. One thing at a time, right? I'm looking for some assistance in identifying the the rear end and brakes. I was told it was an Olds rear w/ 4:10 gearing (Posi). Here's what I'm looking for:

1. Possible year and make of the rear end housing, brakes and center section. See pics below for cast # on the center section and brake cylinder.

2 How can I determine one and for all if it's a posi? If I turn the left wheel CCW, the right wheel rotates CW. When turning one wheel, there is definite force on the other side. Also, this is with the car in Park. The driveshaft isn't turning.

3. Can I determine the ratio without opening it up?

Thank you guys so much for any help. I appreciate your patience in helping me sort this stuff out. I've been out of the car game for a long time and I've definitely got some cobwebs in my brain. I heard this is the best place to go!

Any help or info is greatly appreciated!
Thanks,

Steve-O

 

Looks like the KING of gasser rear ends ..... '57 - '62 Olds/Pontiac 9.3".
Do a search on here for them, lots of info about them.

 

Sure does look like 57-62 Olds like mentioned, axle bolt pattern 5 on 5?

 

Yep, Olds/Pontiac two rib case, there were two rib cases and three rib cases.

 

Take a look at the thread below, page 8 has copy from an article with great info on ID’ing—your casting# 522498 looks to be a first gen. 9.3.

https://www.jalopyjournal.com/forum/threads/pontiac-olds-rearend-tech-post-it-here.129676/page-8

 

Olds 9.3 from 57-58 I believe. My 36 Chevy coupe gasser has one also. The early ones had 29 spline axles and the 59-64 version were 31 spline. Stronger than a Ford 9" and highly sought after. These guys are the only source these days for many of the parts. https://fabcraftmetalworks.com/ Also a tip I found by trial & error if you're needing rear brake drums. The originals were made in 2 pieces are are not available anywhere. 74 C10 pickup 11x2 1/2" rear drums are a perfect fit. Cheap from any auto parts store. When I pulled mine apart it had welded spider gears and a 5.36 ratio ring & pinion...

 

Right on! Thanks so much!!!

 

Thanks for the info!!!! It's a 5 on 4.75.

 

Right on!!! Thanks for the info!!!! Drums are in pretty good shape. It was sold to me as a posi but the axle spin opposite on jack stands. Is that the best way to determine if it's actually a posi? Thanks!

 

Right on! Thanks!

 

Right on! Thanks! There's a lot to sort through!

 

Wow! Yours is CLEAN!!! Thanks so much for the info! What's the best way to determine if it's a posi? The axles turn opposite on jacks. If it isn't, is there a good source for the center section? Thanks again.

 

If the outer wheel turns opposite direction it is a open diff.
Fabcraft is a good source for any parts for these rear ends.

 

Are the axles redrilled to 4 3/4? I always thought Old/Pontiac was 5 on 5.

 

Thanks brother. I had just finished completely rebuilding mine. I got rid of the carrier with the welded spider gears and swapped the ring & pinion to a set of 4.10 gears. If your axles turn in the opposite directions it's not a posi. Factory posi units for these run $1000 bucks and up if you can find one.

 

https://www.speedwaymotors.com/Anse...Gear-Locks-for-Oldsmobile-Rearends,82518.html

Or you can use these to create a locker...

 

Says discontinued. Bummer

 

Big bucks today..