1970 Lemans 10 bolt snafu...please help

[car_guy]

Hey Everyone,

I'm sure this subject has been beaten to death, but I have some questions regarding the 10 bolt in my 1970 LeMans. The casting # on the drivers side lower corner of the center section reads 9799100...all of the data I can find on that code leads me to believe this should be an 8.2". This rear end has the bolt in axles, is a series 2 carrier with 2.56 gears non limited slip, and I believe its the factory rear. Now the rear end has ears on the bottom corners, but they are cut out (not square, but more scalloped). This is where It gets confusing for me. Everything I can find states the 8.2" should have a 1 1/8" pinion nut, with standard right hand thread 9/16 headed ring gear bolts, with u-bolts for the u-joint. Now this rear end has 1 1/4" pinion nut, and 3/4" .437" left hand thread ring gear bolts. I can't seem to find the yoke parts, since I took it apart over 2 years ago, but I swear it had bolts with straps for the u-joint as well. Can someone please school me on this rear end.

But wait, there's more!

If it is infact an 8.5..which I doubt, is it worth building? The main problem I'm going to have is I would want to narrow it 1" per side. I've heard being that its the bolt in axle version, that axles and bearings are expensive. If I narrow it, technically I could change ends, which then maybe I can run different aftermarket axles? Also, since I'm such a rear-end rookie. Is it possible to put a series 3 carrier in it, or am I stuck with a series 2. I've read that to put good gear in a series 2 carrier is with the use of a ring gear spacer, which seems to be frowned upon.

If it is an 8.2 I will scrap it and do something weird like put an 8.8 in.

Thanks in advance.

[raustinss]

Yeah...try to find a 12 bolt,I do recall hearing something about some old 10bolts that were kind of a combo of what gm had left over in the parts bins 8.2 and 8.5 thrown together and stuck into some Pontiac,olds,buicks...hell they even talked about it on fast and loud tv show. A 12 bolt with a rear girdle c clip eliminator 1350 yoke will hold together as high as 600 hp...provided there isn't a lot of " load shocking "
Good luck Ryan Austin

[car_guy]

I've started looking around for the 67 and earlier 12 bolts but no luck. Ive found some 68-72 12 bolts, but for around 1k. Id still wan't to narrow it anyways. Im seriously looking into doing an explorer 8.8 like what RnD did did on project sabre. Its the perfect width for what I need. The hard part would be setting it up. I can pick one up for dirt cheap. Id just really like to find out what's up with this 10 bolt. The curiousity is killing me, lol.

[raustinss]

Don't know where you are living but check Kijiji, there's a guy in Ontario sell rebuilt ones from London and there was a guy selling a used one cheap somewhere north of Toronto, do a all of Ontario search for Chevelle..parts...or even if you can wait the Barrie swap meet is first weekend in June...I sold my spare 12 bolt there about 3-4 yrs ago for 150$ ....just a bare housing I was desperate for cash

[car_guy]

I'm in Alberta. I've seen one as low as $650 in Edmonton, but was hoping I would find something more local to Calgary.

[Nothingface5384]

70 would be a. 8.2 with bolt In axels if I'm not mistaken
Best reared to search for would be an 8.5 10 bolt out of a 71-72 cutlass and same year skylark..bolt In axle..sa.e pinion support as 12 bolt...same goes for pinion shaft diameter.only drawback is you won't be able to get diff like wavetrac. S track or platinum track

If you buy new just get Currie 12 bolt from. Scc..has ford torino ends..no crappy c clips

[raustinss]

$650 is a pretty good deal still...I know it's a bit of a drive over two hours...but would be worth it in my opinion. Plus at that price you could even swap it over to a full floater set up

[Nothingface5384]

Hell I'd take a 1970 Olds type o rear over a chevy 12 bolt with c clips

[Nothingface5384]

You can find 71.72 10 bolts for 150 250 easily..take money saved and upgrade to 30 spline axle and 3/16 retaining plates and 1/2 studs gears and posi..can weld the axle tube also..that alone with just stock 28 splines would get ya into the 10s

[Nothingface5384]

Btw bearings for bolt in axles aren't expensive. .at least my 8.5 wadny..Doubt the 8.2 would be expected site either

[Nothingface5384]

If the cover/axle is rounded..everything smooth its an 8.2

If there's a triangle like ledge below the diff cover it's an ..8.5..fang like would be Olds version of 8.5

[car_guy]

Thanks for the replies thus far everyone,

The 12 bolt for 650 doesn't state anything about condition or gears etc, but I agree its probably the cheapest one I will find. Im still unsure about carriers, and swapping between series. Does the same still apply for 12 bolts as well...just swap to desired carrier series? I would like something in the 3.73 to 4.10 range being I have an overdrive.. If I have this correct, the crappy expensive part of the bolt in axles is they only take 1 bearing, or something like that. Most aftermarket axles supposedly have larger diameter, and don't work with the press on small bearings required? That's where I was thinking if I narrow it (I need roughly 59" wms total width), I can go with a large ford style bearing, or whichever, and run normal 10 bolt axles that aren't specific to the bolt in axle version? There are drag radials on the car, not that I have the power to need them right now, but in the future I would like the rear to be beefy enough to hold up to any non sense I put It through, so you guys are really going to help me decide what to build here. Here are a few pics showing the 10 bolt in question

https://static1.pt-content.com/images/pt/2013/11/billets3_zps5e0b9350-1.jpg (http://s725.photobucket.com/user/carguy_1/media/billets3_zps5e0b9350.jpg.html)
bop cover
https://static1.pt-content.com/images/pt/2013/12/10boltlemans2_zps024b38fc-1.jpg (http://s725.photobucket.com/user/carguy_1/media/10boltlemans2_zps024b38fc.jpg.html)
weird ears on the bottom of the housing
https://static1.pt-content.com/images/pt/2013/12/10boltlemans5_zps9d85eb9b-1.jpg (http://s725.photobucket.com/user/carguy_1/media/10boltlemans5_zps9d85eb9b.jpg.html)
1-1/4" pinion nut
https://static1.pt-content.com/images/pt/2013/12/10boltlemans4_zps20e0301c-1.jpg (http://s725.photobucket.com/user/carguy_1/media/10boltlemans4_zps20e0301c.jpg.html)

https://static1.pt-content.com/images/pt/2013/12/10boltlemans3_zpsa0c8d6dc-1.jpg (http://s725.photobucket.com/user/carguy_1/media/10boltlemans3_zpsa0c8d6dc.jpg.html)
here are the left hand thread ring gear bolts.
https://static1.pt-content.com/images/pt/2013/12/10boltlemans_zpse38cc869-1.jpg (http://s725.photobucket.com/user/carguy_1/media/10boltlemans_zpse38cc869.jpg.html)
9799100 casting number, I also found a light stamp on the back of the drivers side axle tube that says gm 272

[Nothingface5384]

Can you get a better pic of your diff cover

heres an 71-72 olds 8.5 bolt in axle

gfor the 12bolt if you pic it up, yeash cut off axle flange..weld in ford big ends and get custom lentgth axles since you plan to narrow houseing

monzaz jim from JD race could get you a deal for moser axles

[Nothingface5384]

http://www.jdrace.com/diff_id/10bBOP_Buick.htm
here has info on all the 8.2
buick version has bigger pinion diameter compared to the pontiac and the chevy

[raustinss]

A gm a body 68-72 12 bolt will bolt right in...overall without any brakes is 55 1/8". if your running stock wheel wells you will not need to narrow it if you don't want to change the outer bearings to a ford style then stay with stock gm style, if your running rear disc brakes then don't worry about doing a c clip eliminator being as the brakes will hold the axles in if they break,now you can get stock length replacement axles from summit made by Mark Williams I believe the added bonuses being stronger and more importantly they don't have the dreaded taper where the stock ones like to break. I think some people are not thinking here..... follow me with this one
What is the point in rebuilding a 10 bolt....if you can replace it with a 12 bolt (yes btw there are two different carriers regarding gear ratios)... let's be honest they both take the same amount of work to rebuild and costs around the same. so build the 12 bolt..then in the future when you decide to add horsepower..as we all do...then you don't have to worry about the rear end.....makes sense...yes? ...

A 12 bolt at 650$
Rebuild kit. 150$ ish
Axles upgrade 400$ ish
New gears 200$
Simple math tells me that is the cheaper strong way to do a upgrade to the rearend
Prices are rough from memory and year one catalog swap over your brakes and away you go...now add 200$ for a rear end girdle and 30$ ish for oil and additive. suspension doesn't have to even come out of the car. Hell I swapped one 12 bolt for another and didn't even disconnect the brake lines...pulled the drums and backing plate out and up...
Another added bonus is if you swap a 12 bolt in....you never have this issue again of trying to find some obscure rear end 10 bolt..8.2/8.5 hybrid combo thing
Hey nothingface (sorry don't know your name)...why would you want a Olds o type over a 12 bolt....a 12 bolt is gms strongest rear axle at the time...can take up to 600 hp and ft lbs of torque with today's sticky tires...what makes the Olds superior?
Like I said a very quick in and out axle replacement and disc brakes you don't need to worry about a c clip axle braking

[Nothingface5384]

I just dont fancy c clips or c-clip eliminators..

truthfully
the 71-72 buick/olds 8.5 upgraded to 30 spline will be stronger then a 30 spline c clip chevy 12 bolt and the 8.5 would be cheaper starting point
the b/o 8.5 uses same carries/gears as any other gm 8.5 or 8.6
several guys with 71-72 b/o 8.5 rears have been in the 10s several times with just simply welding the axle tubes
also 8.5 yoke will be better then any 12bolt yoke
axle price should be more like 320 -350ish..atleast when i got mine a few years back
only way you may be ahead of the game with factory 12bolt if it had a posi carrier already

I'll stand by my comment when I say the best axle to find and build would be 71-72 8.5
and if you prefer to buy new, currie 12bolt with ford ends

the olds 12bolt/10bolt hybrid type O is strong also, but not sure if you can get everything to rebuild it I wouldnt really use one personally unless i wanted number matching..

edit
just reliazed your in Canada..so yeah if you can find a Canadian 12bolt..non chevy it'll have bolt in axles and the bigger buick u-joint

[raustinss]

I'm thinking your confused as far as I recall the vast majority of all 12 bolts were posi.not 100% sure though. When I refer to a 12 bolt I'm talking a Chevy...as in Chevelle,like ls6. There is no way you will convince me that a 1350 series yoke from a 12 bolt is weaker then a 1310 series 10bolt yoke.
Your comparing a upgraded 10 bolt to a stock 12 bolt, clearly you aren't reading my posts because I just said upgrade the axles
And If you read post #12 there is a mention about a 12 bolt for sale with a carrier he's just unsure of the condition. Therefore he would already have the necessary carrier and only possibly need a new gear set. Which is why I didn't include a price for a carrier or posi rebuild in my previous post.

Also how many 10 bolts do you see behind the cars in the magazines...less then 12 bolts...and less 12 bolts then 9". Based strictly on size the 12 bolt is proven to be a stronger set up. If your going to compare a beefed up 10 bolt then compare. It to a equally beefed up 12 bolt

[Nothingface5384]

rebuild a c-clip 12 bolt with aftermarket 30 spline, and the results are still mute on your end..if youre talking about rebuilding with reg axles with ford houseing ends that were 31 spline -35 spline then yeah, 12bolt would then be top dog

[Nothingface5384]

allot of people dont know about the 71/72 8.5s bolt in axle 3 inch houseing
typically when people talk about 10bolts their either talking about the 8.2s or the lil c-clip 8.5/8.6 version with 2 5/8 housing that come under allot of G-bodies and S10 trucks/blazers
also the yoke doesnt really matter, can use either, and neither will break in a 10 second car

[raustinss]

Okay let's agree to disagree because your clearly not that we'll versed in how to read what I've written and what has been written on such subjects as this in many...many magazines over the years. Yes that "one " rare housing that was offered for only 2 yrs might have been strong but what are the chances. You'll find one...very rare...he has already located a 12 bolt which is somewhat local 2 hours away and will be very easy to find any and all necessary parts for. Remember gm kept building the 12 bolt for a reason...and offered it in many many different vehicles for a reason.....
The 12 bolts issue wasn't the spline count ...it's wasn't even the c clip its how the axles tapers right were the case clip is which then let's the axles come out. Changing the machining on the end of the axles and using a superior steel regains any " lost" strength.
The next biggest issue is the general design and that is the same on all rear ends under hard acceleration the carrier trys to walk right out of the housing which is why I suggest using a girdle (I would in either case. 10 or 12 ) see attached picture of said girdle notice the second picture with the bolts they preload the caps to prevent this movement and flex.
All 12 bolts have a 3" axle tube...........
The biggest thing here as well...his car is a 1970 why are you even talking about a weird 1971-1972 reared housing?

[Nothingface5384]

Okay let's agree to disagree because your clearly not that we'll versed in how to read what I've written and what has been written on such subjects as this in many...many magazines over the years. Yes that "one " rare housing that was offered for only 2 yrs might have been strong but what are the chances. You'll find one...very rare...he has already located a 12 bolt which is somewhat local 2 hours away and will be very easy to find any and all necessary parts for. Remember gm kept building the 12 bolt for a reason...and offered it in many many different vehicles for a reason.....
The 12 bolts issue wasn't the spline count ...it's wasn't even the c clip its how the axles tapers right were the case clip is which then let's the axles come out. Changing the machining on the end of the axles and using a superior steel regains any " lost" strength.
The next biggest issue is the general design and that is the same on all rear ends under hard acceleration the carrier trys to walk right out of the housing which is why I suggest using a girdle (I would in either case. 10 or 12 ) see attached picture of said girdle notice the second picture with the bolts they preload the caps to prevent this movement and flex.
All 12 bolts have a 3" axle tube...........
The biggest thing here as well...his car is a 1970 why are you even talking about a weird 1971-1972 reared housing?

I was tired and kind of watching mob city while typing on my phone and so yeah didn't read everything throughly..

I know about 12 bolts
Yes I'd recommend a rear end girdle type cover too..that and welding axle tube will take you a long way with any axle..

Op sou n did like he'd rather find something closer and cheaper so I gave him a possible alternative.
You act like the 71 72 axel is rare and unable to get parts for them like it's a big task or something lol.

They're no harder to find then then a 12bolt..parts are just as readily available too.

Another option as mentioned of he wanted to too a bit more was the 12 bolts out of the Canadian built cars..which is 12bolt with bolt In axles.
And remark about why am I talking about a 7172 axle cause his is a 70 remark was simply stupid...As both axles aren't factory to his car. But they both bolt up and are stronger.

If he goes for the c clip 12bolt good deal..just beef it up like we both talked about
Just because he has an option right now doesn't me he has to jump on it..always better deals if you're willing to wait
P's magazines don't mean dick ..they just follow more mainstream trends which doesn't always mean better

[car_guy]

Thanks Ryan. Thats pretty much the question at hand...what to do with this niche rear end. The other part I was thinking about, if it was an 8.5 that maybe I could sell it and re-coup some funds for a new one, but I don't think its really worth anything...and the next guy will be just as confused as I am. I guess I didnt think building the 12 bolt would be that reasonable. The last 12 bolt I had built in a 70 chevelle(I don't have the tools to set up the gears) cost me $1900. That being said it was a bare housing, so I had to buy everything (3.90, true trac, can't remember axle brand, no girdle, etc) and the guy even installed my brakes (custom shop who I was buying my parts from anyways). That's what was driving the uncertainty of buying another 12 bolt of unsure condition, then the cost of parts, plus the cost of narrowing. I was looking into moser, and a new one less brakes looked like it was around $2500, so there's that option too. Then at least there's peace of mind if a guys going to spend that money anyways. I know the 64-72 rear ends all bolt in, but the 68-72 rears are 61" wide, and the 64-67's are something like 60" total width to wheel mounting surface. It must be the cheap ass in me that was thinking to find a ford rear end and make it work. My luck though, then a guy still has to re-build the junkyard diff anyways, haha.

[Nothingface5384]

Thanks Ryan. Thats pretty much the question at hand...what to do with this niche rear end. The other part I was thinking about, if it was an 8.5 that maybe I could sell it and re-coup some funds for a new one, but I don't think its really worth anything...and the next guy will be just as confused as I am. I guess I didnt think building the 12 bolt would be that reasonable. The last 12 bolt I had built in a 70 chevelle(I don't have the tools to set up the gears) cost me $1900. That being said it was a bare housing, so I had to buy everything (3.90, true trac, can't remember axle brand, no girdle, etc) and the guy even installed my brakes (custom shop who I was buying my parts from anyways). That's what was driving the uncertainty of buying another 12 bolt of unsure condition, then the cost of parts, plus the cost of narrowing. I was looking into moser, and a new one less brakes looked like it was around $2500, so there's that option too. Then at least there's peace of mind if a guys going to spend that money anyways. I know the 64-72 rear ends all bolt in, but the 68-72 rears are 61" wide, and the 64-67's are something like 60" total width to wheel mounting surface. It must be the cheap ass in me that was thinking to find a ford rear end and make it work. My luck though, then a guy still has to re-build the junkyard diff anyways, haha.

good option if buying new
http://scandc.com/new/node/525
Being a 70 you dont need to narrow axle..with a 12bolt out of 68-72 or 8.5 out of a 71-72, your given bodystyle will easily fit 15x10s with a 325-50 or 17+ with 315s

most you may get for selling that 8.2 would be about 250 max

[car_guy]

good option if buying new
http://scandc.com/new/node/525
Being a 70 you dont need to narrow axle..with a 12bolt out of 68-72 or 8.5 out of a 71-72, your given bodystyle will easily fit 15x10s with a 325-50 or 17+ with 315s

most you may get for selling that 8.2 would be about 250 max


Ive already got wheels and tires, 17x11, 5.5: bs with 295/45/17. The fit now, but If im going to build a diff, Id like to pull them in an 1" or 1.25" per side to get them to tuck as I want the car to be low. Buying new would be nice...I better start saving my pennies...250 isnt bad, even if i get $150 out of it Id be happy.

[Nothingface5384]

good deal, was curious to why you wanted to narrow, now I know

[raustinss]

Nothingface it was 3am here was also tired glad we got that cleared up lol

Aaron as of last night at midnight here...there was three 12bolts which would fit your car
#1 guy is selling a whole drivetrain
#2 guy is selling just rearend includes a Eaton posi and 4.11 gears
#3 is guy from Edmonton which you know about

The other 2 are both in Calgary area...all are on Kijiji...look under Chevelle...parts...all three were found in the first three pages.
Look at my second picture I had a guybtig weld around my axle tube and reweld the factory plug welds because I snapped a upper control arm and 2 of the 3 plug welds. Nothingface is right you can build that rear end but I believe a 12 bolt to be stronger he provides a link for info about your rearend 68-70 BOP (Buick olds Pontiac )
A 64-67 rear end won't quite work as the control arm and coil mounts are slightly different, only going from what I was told when I was looking for another 12 bolt, so if your going to go the 12 bolt route..narrow it your 1" and get the axles tunes welded at the same time . You are right about narrowing it to create comfort room if you lower the car. I found it does get a Lil tight when the car is loaded and lowered just do to the shape of the wheel wells. They narrow at the top.
Both you and Nothingface should check out the safety thread written just lastnight on here..has some info regarding rear ends...the stupid axle taper..where they like to snap...bearing loads..C clips etc.
I agree with Nothingface his price for your rear is almost perfect. Page 7 maybe on Kijiji search I previously mentioned has a guy selling a empty 10 bolt housing for 150$ so you should be able to get 250$ easily
I forgot to include in my parts breakdown
Forged...not billet..not cast...12 bolt 1350 series yoke 150$ I got mine from a guy on eBay. But if you do upgrade the yoke to a 1350 you need to get a new matching yoke on your driveshaft I got mine done at a heavy truck place for not even 200$
Please anyone with any more info toss it on here Nothingface did teach me a Lil bit about some of the bop 10 bolts having said that your only stupid if you don't continue to learn so please educate me
Aaron keep us updated as to what you do and throw up some pictures to.. Thanks
Good luck Ryan Austin
[email protected]

[Nothingface5384]

Nothingface it was 3am here was also tired glad we got that cleared up lol

Aaron as of last night at midnight here...there was three 12bolts which would fit your car
#1 guy is selling a whole drivetrain
#2 guy is selling just rearend includes a Eaton posi and 4.11 gears
#3 is guy from Edmonton which you know about

The other 2 are both in Calgary area...all are on Kijiji...look under Chevelle...parts...all three were found in the first three pages.
Look at my second picture I had a guybtig weld around my axle tube and reweld the factory plug welds because I snapped a upper control arm and 2 of the 3 plug welds. Nothingface is right you can build that rear end but I believe a 12 bolt to be stronger he provides a link for info about your rearend 68-70 BOP (Buick olds Pontiac )
A 64-67 rear end won't quite work as the control arm and coil mounts are slightly different, only going from what I was told when I was looking for another 12 bolt, so if your going to go the 12 bolt route..narrow it your 1" and get the axles tunes welded at the same time . You are right about narrowing it to create comfort room if you lower the car. I found it does get a Lil tight when the car is loaded and lowered just do to the shape of the wheel wells. They narrow at the top.
Both you and Nothingface should check out the safety thread written just lastnight on here..has some info regarding rear ends...the stupid axle taper..where they like to snap...bearing loads..C clips etc.
I agree with Nothingface his price for your rear is almost perfect. Page 7 maybe on Kijiji search I previously mentioned has a guy selling a empty 10 bolt housing for 150$ so you should be able to get 250$ easily
I forgot to include in my parts breakdown
Forged...not billet..not cast...12 bolt 1350 series yoke 150$ I got mine from a guy on eBay. But if you do upgrade the yoke to a 1350 you need to get a new matching yoke on your driveshaft I got mine done at a heavy truck place for not even 200$
Please anyone with any more info toss it on here Nothingface did teach me a Lil bit about some of the bop 10 bolts having said that your only stupid if you don't continue to learn so please educate me
Aaron keep us updated as to what you do and throw up some pictures to.. Thanks
Good luck Ryan Austin
[email protected]

I'll check it out, actually have a somewhat safty question with carrier journels and 33-35 spline shafts

[car_guy]

Thanks for the info, and the help guys. It will probably be a little down the road but I will update in my build thread for sure.