1970 Camaro RS 350CID roller rockers (10 bolt Non-Posi) want a 12 bolt posi swap --

knightmoose

Veteran Member
Jul 24, 2010
161
Phoenix Luke AFB
I have seen a few COS dated 1970 Camaro 12 bolt "1 yr only" rear ends sell upwards of $2-3k for a rusted rear end that needs everything redone, bearings, the posi, the gear ratio changed out, spindles replaced you name it;

****I'm up in the air thinking about what rear end to throw $$$$ at ....

Question; Would you throw $$$ at a (dated 1 yr only COS GM stamped rear end for the 1970) vs. buying a new warranted "Moser" dropped ship to a shop where it bolts right on complete done?
 
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Gary S

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Lifetime Gold Member
Apr 14, 1999
24,648
Bismarck, North Dakota
The Second Gen Camaro 12 bolt is a low production differential because it was used only one year, and only on Z28 and SS cars. Finding a reasonable priced one can be difficult. The 3.55 ones are probably the highest priced ones as they were used only on the L78 SS396. The 3.73 and 4.10 were made in larger numbers, but will still be high priced as they came in Z28 and L78. You might be able to find a 3.31 or 3.07 from the SS396 L34 or the SS350 for a better price. The 3.31 is probably the best all around gear for street driven cars so if that works for you, look for one of those.
 

streak

Member
Apr 27, 2021
56
Unless you are doing a numbers matching show car then you get way more performance bang for your buck with a new unit. As you saw, date coded you pay a ton for something with old components likely in need of updating for a car with decent power or matching to your driveline needs.
Having a new posi, the perfectly matched gear ratio, updated tube ends, fully welded body, larger spline axles, etc is worth it when upgrading anyways.
 

Lowend

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Mar 25, 1999
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San Jose, CA, USA
Agreed, for anything other than a matching numbers show car, the Moser is equal or superior in every way.
That said, the 8.5" 10-bolt is a damned strong differential. I personally ran 500 horsepower on race tires for years and hundreds of auto-x laps without so much as a sound. It's lighter than the 12-bolt and with unsprung weight that makes a difference.

Now the 8.2" 10-bolt that came in the 1st gens, or the 7.5" that came in 3rd and 4th gens are different stories.
 

Gary S

Administrator
Lifetime Gold Member
Apr 14, 1999
24,648
Bismarck, North Dakota
If your existitng 10 bolt is original to your '70 Camaro, it would be the 8.2" rear which isn't as desirable as the later 8.5". There are lots of 8.5" ones available from the 71-81 F body cars you could use.
 

1980RS

Veteran Member
Jun 17, 2006
6,546
MN
A 68-72 Chevelle 12 bolt is the same length as a 2nd gen Camaro rear end, but you will need to cut the lower mounts off and add the spring perches to make it work in the Camaro.
 

knightmoose

Veteran Member
Jul 24, 2010
161
Phoenix Luke AFB
I doubt its the original 10 bolt -- I dont have the Proetect-o-plate to the car so im leaning to what others have stated in this trend; I did find a 12 bolt with 3:55s dated for the 70 1 yr only etc after shipping its close to 3k which is why im leaning towards the Moser at $3100 shipped because "rebuilds are in the eye of the beholder "- and id rather have everything new...
 

knightmoose

Veteran Member
Jul 24, 2010
161
Phoenix Luke AFB
Agreed, for anything other than a matching numbers show car, the Moser is equal or superior in every way.
That said, the 8.5" 10-bolt is a damned strong differential. I personally ran 500 horsepower on race tires for years and hundreds of auto-x laps without so much as a sound. It's lighter than the 12-bolt and with unsprung weight that makes a difference.

Now the 8.2" 10-bolt that came in the 1st gens, or the 7.5" that came in 3rd and 4th gens are different stories.
The 10 bolt in my 1970 Camaro isn't posi & it "pops/chirp" "skip's" kind of "at the jump", thus i'm not wanting to dump $$$ into it to make it posi & or fix clutch or bearings - It would run close to $1600-$1800 from local shops that charge upwards of 250$ per shop hr. so im not wanting ti dump $$$ into a 10 bolt non posi --- "I'd prefer a Moser 12 bolt" & can pick 3:55 gear ratio w/30 spline; vs. the Strange & or 9" Curry Fords-- I personally don't want any "Found on road dead Ford parts" on my 70 Camaro so that rules out the 9"-- a local shop in Phoenix stated they could build a 12 bolt installed at $2800 BUT it's a rebuild vs. "Moser that has a reputation";
 

sandlapper

Veteran Member
Oct 9, 2020
1,622
SE CSA
9" typically have more options and wider use (across the hobby) --- thus cheaper $ economy of scale.
Nuttin' tougher (except perhaps Dana 60).
So --- how much is a new 9" set up to suit your car?

I get the brand loyalty thing --- but every CT car I've worked with had either 9", 9" floater or a quick-change (& those often use 9" R&P).

GO MAX!
 

Lowend

Administrator. .a car, a man, a maraca.
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Mar 25, 1999
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San Jose, CA, USA
(-) for the 9”: you’ll probably need a different driveshaft to fit it. The u- joint size on the factory driveshaft is wrong

(+} for 9” they can be shipped via ups instead of truck freight

Potential (-) I’ve heard tales of people having issues with rear sway bar figment and the pumpkin. Never seen it in person, but could see how it could be an issue
 




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