I think i have a 1967 cutlass 12 bold non posi olds rear end in my 67 442. I pulled a posi internal unit only out of a 1969 delta 88 12 bolt "See Pics"
Is this going to fit in? From what i have been reading it does not interchange. B body 12bolt post to an A body 12 bolt. Did i read up on this correctly or is there any other way to make it fit?

 

Most unlikely

if only it were that easy!

Isn't the B-C body ring gear like 9 & 3/8" OD?

 

Well ok i have to keep an eye out for something to put in. I wanted to know if anyone knows what should have been in my 1967 442?
When i got the car it had a 10 bolt that would only light up one tire. I broke that the end cap blew up and i threw it in a dumster thinking it was only a single track and it probably was not origional. I didn't know to look and see if it was a posi that just needed some tlc. I think me and a friend jacked it up and figured it might be a 342 or something like that. I probably threw out an origional posi that just needed a rebuild! Any way any thoughts as to what i should keep an eye out for?

 

I believe the 67 442 could have come with the Pontiac style 10 bolt cover rear or the Olds 12 bolt. I do not think a posi was standard in the 442. For an automatic trans car the rear gear was most likely a 323 gear especially if it had AC. The stick cars generally came with a 355 gear but other ratios could have been ordered.

 

Have you researched here:

http://www.oldsmobility.com/old/reardiffs.htm

 

First, your stock Type O is not a "12 bolt". It may have 12 bolts on the cover but the 8.5" ring gear is retained with only ten bolts. NOTHING else swaps in. As Chris pointed out, the full size axles use a 9 3/8" ring gear.

 

This is a good link thanks

 

Understood, but now that I want to look for a replacement should I look for a posi for the 12 bolt "cover' type I have, or should I look for a whole unit 10 bolt posi? I see the link in the previous post indicated I should have a Posi 3.23 G-91, 3.42 G-92, 3.55 G-93, But it does not tell me if these were 10, or 12 bolt?? What origionally was correct for my 1967 442? 10 or 12

 

It will all depend on your build date and where it was built and the biggest fator...IS your diff original to your car... 45 years ALOT can and did happen. Jim

 

Let me ask it this way. What rear would my car have in it from the factory? Right now it is not the origional and if i need to replace it i will try to get something that looks car and time period correct. If it is way to much money or made of "unobtaneium" i might go with something that is reasonable but not realy what they came with. i.e.cheby if it is cheep and will fit in without many modifications. the attached is my cowl tag for identification purposes.

 

Well it seems you are "not getting" it from the info posted. Your 67 442 could have come with the 10 bolt cover Pontiac rear with bolt in axles OR the 12 bolt cover Olds rear. BOTH REARS were used and it would depend on build date and build locations as to what one your car came with. To specifically say what one YOUR car came with would be only a guess. Either one would be correct. I have also heard that Canadian built car came with the 12 bolt Chevy rear with C clip axle retainers but am not sure of this. My 67 442 conv cam with the 10 bolt cover rear. I parted 2 67 Cutlasses recently. One had the Olds rear and one the Pontiac. My advice is to find either one with posi and install it.

 

If you cannot use this posi unit would you want to sell it ? If so how much ? Thanks Where are you located ? BOB

 

I have a one wheel squeel 12 so I guess I have time to look locally for a 12/10 inside, but I believe the 10 whole unit posi would be nice if I stumble on one near by. I have some good info and will still look over more posts so I am well versed when the time comes. Thanks

 

I have not researched what would be a fair price, I live in Massachusetts near the Rhode Island line. I did want to put it in my 12 bolt. Now that I can not use it I would be considering selling it to some one that can use it.

 

How many bolts are on the ring gear of the posi differential you bought?

I know my '68 Delmont 88 (350) has the same 12-bolt cover/10-bolt differential as my '67 442 has. I believe 350-powered Deltas also used this rear in '69.

OK, nevermind. I just re-checked your pics and see you have a #700 carrier - which is definitely the big Olds 12/12, 9-3/8" unit used in 455-powered cars only. It will only take a 2.56 gear.

 

I think i am getting it now. If it is 12 bolt it is olds with a 10 bolt inside. if it is a 10 bolt outside it is a pontiac 10 bolt in an oldsmobile, because olds did not make a 10 bolt outside and inside.

 

wouldn't that be an 8.2" ring gear?


bill

 

Will the 1965 Pontiac Rear End swap into my 1967 442 with no problems?
I found this craigslist post near me

1965 GTO GS 10 Bolt Posi Rear End very clean from California $625
http://boston.craigslist.org/bmw/pts/3508169226.html

 

Not sure but that rear may be slightly shorter than the 67 rear. Also the spring mounts are different than the 67...

 

I don't have a huge experience with the Delta's,but from what I have found,the 68-70 that came equipped with a 350,had the 12-bolt O-axle center.The ones that came with the 455 had the larger center.

I have pulled a few 350-equipped Delta rears apart,to find the same #671 carrier,and either 3:08 or 3:23 gears.I'm not saying ALL of the Delta's have decent gears either.I only grabbed them because they had a posi tag on them,and found the better treasure inside.

 

Thanks, I won't waste my time with that one. I will keep on the search I still have time to look locally. By the way if I had a 1967 10 bolt one wheel squeal I could have used that 1965 10 bolt posi unit only for trans plant right? Oh I would have to see how many splines i have on the 10 bolt i don't have yet.
Hmm
This might be what I will do next.
1) Look for a posi that is from a 1966/1967 olds.
2) Count my axel splines in the 12 bolt then know what i am looking for.
3) Get a cheep 10 bolt single wheel, count the axel splines look for a posi carrier.