Technical 9.3 Oldsmobile Pontiac Rear Axle and Posi

Hello, I am just learning about these and I am going to order the manual that is available online.

I am a Chevy guy so I am used to various "series" posi units that will only accept a range of gears (though some of this has changed in last 20 years that you can now buy 4:11's for say a 3 series 8.5 10 bolt posi unit).

Do the Olds Pontiac differentials follow the same rules, say if I find a 9.3 that had say 2:73 gears, is there a way to put 4:11 or 4:56 on it with the right gear set or spacer set up?

I appreciate the insight, I am sure there are many here in the know.

Regards, Tim

 

Yes.

Link for parts https://fabcraftmetalworks.com/

 

Fabcraft has everything you might need....they even sell used housings and center chunks. Best bet is to find the last version if you can (series III) or at least the series II.

 

Yea. FabCraft did my entire 9.3. 4:88 gears, chrome moly heat treated axles, seals, bearings, everything. Not cheap , but damn near indestructible.

 

If you plan on racing it, the three rib pumpkin is the one to look for.



More info

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

 

If I was going to use this in a race car I wouldn't use a ring gear spacer.

 

A few more pictures of the FabCraft 9.3 in the coupe.

 

That's what I had in my 65 Malibu bracket car in the mid 70's, 5.38's.

 

Maybe I should dig my 57 rear out from under the shelf and post a pic as well?

 

In my most "manly man" voice.........I'd like to see your rearend!
I remember that a large number of the cars I would see in the magazines in the mid 60's as a blooming hot rodder had Olds/Pontiac rearends, long before the Ford nine inch became popular.
I really started paying attention when I started snapping axles and blowing up third members in my 57 BelAir, that was with a tired 283/T-10 four speed, I contemplated a rearend change but decided to leave it alone and start with a different car.
When I bought my 65 Malibu as a roller it already had the Olds/Pontiac rearend in it, it was the first time of actually seing one in person and thought man that thing is huge compared to the 57 Chevy rear.
Really making me nostalgic thinking back to those days.

 

We run one in are 62 BelAir race car.

 

Sounds fishy to me.

 

Jesus Gee!

 

I ordered the manual, I have a few 3 rib cases, quite a few sets of axles and housings, spooled 3rd member, few other 3rd members - I have a line on a couple posi units now

 

Does a casting number of 30942 on the case give any insight on what a unit is? I have a line on a posi, thanks

 

That doesn't sound like enough numbers for a casting number.

 

No need to wreck your back, I can share pics... hahahaha!











I'll see @mad mikey and raise him.

 

Actually my back is a wreck (L3) and been doing light things these last few day’s. But if I was to go to the other house I wouldn’t pull it out even if I felt good. You all would have to settle for a snap shot of it where it lay’s.

Liking the drain. I added one to mine.

 

I run a spool but it is a race car.

 

What operation are you doing here?

 

Narrowing it.

 

Anyone have ideas of what brand axles these may be? guessing early aftermarket, they are 31 spline 9.3

 

57 & 58 9.3’s are 29 spline and width of housing was narrower. That’s why tri five guys like the 57/58. 9.3’s went to 31 spline in 59 & up and axles were a little stronger but also wider.

 

yea all of the ones I have are the stronger 3 rib versions

 

If you are right there is a good chance they were made by Henrys in L.A.
They were IT back in the day.

 

Don't know what brand they are but they don't look too useable with those twisted spline's.
They might just be redrilled stocker's.

 

yes, saw the splines, these came with a big 9.3
parts buy I did

 

In the late 70's I owned a former pro stock Ford drag car (OT), it had been powered by a 427 SOHC.
The nine inch rearend had Henrys axles that had twisted splines, when I asked around I was told they were known for that but they would not twist further.

 

The hub portion doesn’t like any thing like the stock ones I have. Could they be Summers?

 

This discussion may be helpful, keep in mind this site is geared toward newer (OT) stuff.

"I has Henry axles in my chassis research dragster never broke them! they twisted one whole spline but held up to 600 hp for 10 years ".


Here:
https://www.digitalcorvettes.com/threads/henrys-race-axle-shafts-running-springs-california.157190/