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