How to tell difference between 8.5 and 8.2 10 bolt

Discussion in 'Got gears?' started by tinker14bs, Apr 21, 2009.

  1. tinker14bs

    tinker14bs Well-Known Member

    I have a 69 Buick Skylark Custom that I was told has a 71 GS350 rear end in it. I know it is a 10 bolt non-posi and I want to get a posi carrier for it. So questions are weather I can get a posi carrier for the 10 bolt, and how to tell if it is a 8.5 or 8.2. I thought I read an 8.5 is better to have then an 8.2. Also would it be better to try and find a 12 bolt posi instead of putting in a posi carrier to the 10 bolt? I have a mildly built Buick 350 in the car with a TH350 in it currently. Thanks for the help.

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    Last edited: Apr 21, 2009
  2. carmantx

    carmantx Never Surrender

    I believe it is an 8.5 because of the square tabs on the bottom corners.

    The 8.5 is plenty stout if built right.
     
  3. V8Sky

    V8Sky "Scarlett"

  4. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD" Staff Member

    Looks like an 8.5 to me. Square lugs sticking out of the bottom of the pumpkin. Take a look at where the rear u-joint cups attach to the yoke. An 8.5 will use cap screws and metal brackets. The 8.2 will have u-bolts and nuts. The 8.5 is a very sturdy rear. Get a good Posi for it. Parts are easily accessible. In addition, the Buick 8.5 uses bolt in axles, superior to the 12 bolt's C clips. The 8.5 10 bolt has the same pinion support as the 12 bolt. It will easily stand up to whatever your combo will throw at it. Keep the 8.5.
     
  5. 70 gsconvt

    70 gsconvt Silver Level contributor

    Another good way to check is to look at where the axle tubes go into the center section. If it's smooth, it's an 8.5. If there are 4 bumps around it, it's an 8.2.
     
  6. tinker14bs

    tinker14bs Well-Known Member

    Thanks for the help. It is an 8.5. It has the straps holding the driveshaft on. Now I just have to research a posi carrier and what gears I should use. The car will be used for recreational driving. Maybe take a trip to the strip, but very rare. I am thinking a 3.08 would be good or else a 3.23.
     
  7. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD" Staff Member

    I have the Eaton Posi. They are available anywhere. This is the one you need.

    http://www.jegs.com/i/Eaton/362/19557-010/10002/-1

    If I was you though, I would PM board member Monzaz. I bet he can give you a great price on what you need.

    http://www.v8buick.com/member.php?u=3880
     
  8. monzaz

    monzaz Jim

    THis information is backwards. The 8.5 has the casting 4 bumps and the 8.2 is smooth.

    The rear is a 8.5 100% NO ifs and or BUTTs. :) Build it. Jim
     
  9. wkillgs

    wkillgs Gold Level Contributor

    So were the 71-72 A-body Buicks and Olds the only ones to use that particular housing?
    I'd like to build an 8.5 for my '66 GS. I do realize the later rear may be a bit wider than my 66.
     
  10. GStage1

    GStage1 Always looking for parts!

    Yes, only Cutlass/Skylark for 71-2 have the 8.5"
    You can install the 8.5" in your 66....it will be 1" wider.
     
  11. monzaz

    monzaz Jim

    That is correct...I have HEARD... this is all hear say NOW that el caminio got them put in fo some weird reason? BUT I personally have never seen one yet.

    Here is another one...I just sold a gentleman a posi for a 8.5 today for a 1970 gs that had a 10 bolt 8.5 under the car and MARKED on the axle tube OO

    NOW, I know for a FACT the car is 8.5 because he sent pictures of the and we got in a big todo aBOUT WHAT IS SUPPOSE TO BE UNDER THE CAR. soooo THIS IS VERY INTERESTING INDEED. yeS?

    jUST THOUGHT i WOULD LET YOU GUYS KNOW.

    i WONDER WHAT pLANT THE CAR WAS ASSEMBLED IN? jIM
     
  12. GStage1

    GStage1 Always looking for parts!

    Interesting info Jim.....I would bet that someone made the 8.5" stamp "00"
    No way, no how it has an 8.5" from the factory.

    Also, rumor I have been told....some 81-84 G-body wagons have the 8.5" rear.......BALONEY......I always use empirical evidence from my yarding trips and so far.....never found one G-body wagon with an 8.5"

    I don't know where the mis-information gets started but nice to have a forum like this to put an end to it.
     
  13. monzaz

    monzaz Jim

    I told the guy to send pictures ...so will see. I have always learn to never rule anything out especially if it is at the end of a run or the beginning. GM has done this MANY times with s-10 full size trucks etc. Just today a gentleman called me on a 1999 1/2 10 bolt and it still has the 8.5 rear when it should have the 8.6 rear...???

    If this rear were in a 68 or 69 I would have to totally say NO WAY...but it is a 1970 and it is a GS.... It does make me wonder and I would also love to get the build sheet for this car or at least a date the car was produced and the plant.

    I will try to get more info and pictures for the fun of it at least. JIM
     

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