Question on 68-72 Olds type "O" Rear
 

when changing gear ratio in this type differential, do you need to change carriers like you do in a "C" type 12 bolt ? this is the 12 bolt cover with the 10 bolt ring gear. changing gear from a 3:42 to a 4:33. thanks !

Re: Question on 68-72 Olds type "O" Rear
 

Joe, Same case they just made the ring gears really thick.

Re: Question on 68-72 Olds type "O" Rear
 

Joe;
I went from a 3:23 to a 4:66 (GM gears) in the "O" rear.... in my '70 f/85...

Re: Question on 68-72 Olds type "O" Rear
 

With OEM stuff, Olds parts had the same carrier for all "heavy duty" ratios, 3.42 to 5.00. The rear was used from late 1966 to 1970. The HD stuff wasn't readily available until 68; in 69 Olds went from 31 spline axles to 28 so the carrier side gears changed, of course.

Re: Question on 68-72 Olds type "O" Rear
 

Glad to see this post! This is going to be interesting...

Re: Question on 68-72 Olds type "O" Rear
 

Thanks for all your responses. Danny, we are going to move forward on this project a little at a time. Fred installed a line-loc and drag shocks this past weekend. The gears are next. We are seeing how much we need to do to run a tad below the E/Pure Stk. index without drastically altering this pristine all origional muscle car. Only 13K origional miles on odometer !
Bob, I am anxious to see this through, I believe car has potential. When Fred had it at Piedmont last weekend, I was amazed at the folks coming over to check his car out. They walked right past mine and didn't bother ! LOL !!

Re: Question on 68-72 Olds type "O" Rear
 

Wow ! 13,000 miles ! Are you boys sure you want to do this ?

Re: Question on 68-72 Olds type "O" Rear
 

Fred will not do anything to devalue this car. Better to have some fun with it rather than it sit in a garage to just look at.

Re: Question on 68-72 Olds type "O" Rear
 

Re: Question on 68-72 Olds type "O" Rear
 

Well it looks like I have procured a ring and pinion set.....

http://i143.photobucket.com/albums/r...433gearset.jpg

(picture for Mark...lol)

My question is ....as these are original GM pieces, will they fit the 3:42 carrier that is in the car now? I have 31 spline axles. I have heard of a spacer being needed on some of these applications.Would I need a spacer with a factory set of gears vs. aftermarket or visa versa? Just want to make sure before we dig into this..Any help on this will be appreciated.

Regards,
Fred

Re: Question on 68-72 Olds type "O" Rear
 

Hi Danny,
Not going to do anything that cannot be undone easily. Like Joe H. mentioned better than looking at it in the garage. lol. I really think it appreciates being run hard with hi octane.

Regards,

Fred

Re: Question on 68-72 Olds type "O" Rear
 

Beautiful car Fred--------Go for it , just smear vasoline all over EVERYTHING behind the rear wheels :)

Re: Question on 68-72 Olds type "O" Rear
 

I want to see that 13,000 mile car!

Re: Question on 68-72 Olds type "O" Rear
 

Not a bad idea....probably go into the trailer easier too.

Re: Question on 68-72 Olds type "O" Rear
 

Might help you get out of the car when its in the trailer. LOL.

Seriously, a lot of the pro stock guys spray PAM in the wheel wells and lower quarters so cleanup is easier.

Re: Question on 68-72 Olds type "O" Rear
 

It's been awhile since worked on any of those rears,I was trying to remember but not sure but I think you could put 12 bolt unit in those rears if I remember correctly.
Mike Taylor 3601

Re: Question on 68-72 Olds type "O" Rear
 

I don't think a 12 bolt posi will go in. Olds used the same posi from 3.42 to 5.00 ratio.

Re: Question on 68-72 Olds type "O" Rear
 

No, unfortunately you can't put a 12-bolt Chevy carrier in an Olds housing. Funny thing is, although the "O" type had a 12-bolt cover, the carrier used 10 bolts to retain the ring gear. I wish I had a nickel for every time someone told me they threw one of those out years ago. An "O" type rear with positraction can go for pretty good money nowadays. Richmond does offer new 3.42 and 3.91 gears for the "O" type if anyone needs 'em.

Re: Question on 68-72 Olds type "O" Rear
 

Thanks for the verification Jim.....we found this when we pulled the cover off. I thought the same for years.Found a 4:33 set in OKLA.

Re: Question on 68-72 Olds type "O" Rear
 

so what is one worth ?
i got one dissassembled with a new 3.90 gear ?
just wondering

captain jack

Re: Question on 68-72 Olds type "O" Rear
 

Jack: Quite a bit to a guy restoring a '67-70 Olds 4-4-2, H/O, etc. that wants the correct rear. I would think that a complete "O" type positraction rear with 3.91 gears would be worth between $2,000 and $3,000. I had a fellow offer me $1,500 for one that I have in my street '70 4-4-2, and that was 15 yrs. ago.

Re: Question on 68-72 Olds type "O" Rear
 

In the early 70's Dale Smith used to send those things along with Muncie 4 speeds and Bonzi 400 turbos to us by the pallet load 4.66 and a few 5.00. All brand new but each had a label attached saying scrap. I still have a few of those labels in my tool box. The 82 Cutlass they sent us had no vin # and also labeled scrap. ------ He knew we didn't use any of it but couldn't directly give us money so that was his way of helping us finance our racing. Gave that stuff away compared to todays prices. All aluminum W27 O type 12 bolts bring $ 8000 plus to the right guy these days. Never sent us any of those, they came cast iron with a W27 cover on them. Kinda glad he didn't if you get my drift. :)

Re: Question on 68-72 Olds type "O" Rear
 

Cool story, Danny.

Re: Question on 68-72 Olds type "O" Rear
 

Looks like that ring gear is quite thick. Should go on your existing carrier
OK. Should help in the ET department. Good luck, take good care of that car!!

Re: Question on 68-72 Olds type "O" Rear
 

Jim-------- Dale was a great guy who loved these cars and would do anything in his power to help keep you going. A successful Olds at the track whether a 1950 or a brand new one was the same to him. Although manufacturers cup points were only earned with current model year cars he kept feeding us anyway. He loved the fact that we were running a 4 speed and had locally won 36 out of 45 eliminators in 1973. He said the best exposure and biggest sales came from local tracks. In 1974 with a 2 year old Cutlass he sent us his own personal Exxon credit card so we could go to Gainsville for the Gator Nationals. He was a hell of a guy and I will never forget how he treated two nobodys from Virginia that came up to visit him in 1973. He and two engineers Ron and Tom ( can't remember their last names but bled Oldsmobile performance ) took us to a place called the Red Rail Inn in Lansing and had some guy named Johnny Walker do his best to kill us. Great times and even greater people. :)

Re: Question on 68-72 Olds type "O" Rear
 

umm...wasn't exactly "two nobodys from virginia"
you sure made MY Olds wake up ha ha
how are ya buddy?

Re: Question on 68-72 Olds type "O" Rear
 

Hey guys .Any sets of 5.0 "s around ?

Re: Question on 68-72 Olds type "O" Rear
 

Hey Glen, Good to hear from you and hope all is well. It's not the same without you hanging out with the Olds contingent. All three of us. :)

Re: Question on 68-72 Olds type "O" Rear
 

Not a class racer (just a brkt racer), but love my Olds, and have, for going on 43 years.... :)

Re: Question on 68-72 Olds type "O" Rear
 

Sorry but all that stuff I had is long gone now.

Re: Question on 68-72 Olds type "O" Rear
 

Bob----------- That makes you a bracket racer with CLASS !------------:)

Re: Question on 68-72 Olds type "O" Rear
 

Thank you sir.......

Re: Question on 68-72 Olds type "O" Rear
 

Bob,I think your car will fit into Stock sooner than you think.

Re: Question on 68-72 Olds type "O" Rear
 

I know what you are saying, Daryl... ;-)
That's why I quit trying to build my car into a S/SS back in the mid '70's... I would buy the latest and greatest "go fast" part, and it would be "obsolete" before I could install it.... The rule changes, moved too fast for me.... and my wallet. :0