1965 skylark rear end swap question.

Discussion in 'Got gears?' started by robert v, Oct 23, 2017.

  1. robert v

    robert v Well-Known Member


    I'm looking to swap my complete stock rear diff. (drum to drum) for a posi rear.
    Please advise what years will be a bolt on replacement. I think its 8.2

    Can I use a rear from Chevy, Olds Pontiac ?

    found a complete rear diff from a 1968 Chevy Chevelle factory 4 speed (308 posi).
    Will it be a direct bolt on fit?

    Last edited: Oct 23, 2017
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  2. philbquick

    philbquick Founders Club Member

    It will bolt in. Chevy uses a slightly different u-joint, clips on the outside of the caps instead of the inside like a Buick. It seems like someone makes a u-joint that is Chevy one way and Buick the other.
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  3. Golden Oldie 65

    Golden Oldie 65 Well-Known Member

    Phil is correct. Most parts stores should have the 1330 to 1310 u-joint. Well, maybe not most stores. I would probably avoid the chain stores. All they would give you is a blank stare., but Napa should be able to help you.
  4. BrianTrick

    BrianTrick Brian Trick

    If it's not on their monitor screen,they won't have any idea. I use them occasionally,when swapping a BOP rear into a Chevy. Some people refer to them as an adapter U-joint or hybrid U-joint. If you don't have any luck,I can get them here.
    The only other difference with that 68 Chevelle rear,compared to your original,is the overall track width. The 68 rear will be 5/8" wider on each side,which will move your wheels outboard 5/8". If you have the original stock wheels,you will be fine,but if you have aftermarket wheels that are wider,and barely fit under there,you might want to check that.
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  5. philbquick

    philbquick Founders Club Member

    Forgot about that!
  6. wkillgs

    wkillgs Gold Level Contributor

    Brake hose is different too.
    65 uses 1/4" brake line, 67-up is 3/16".

    Edit: to clarify, the brake line on the frame, from master cylinder, is a different diameter. The hard lines on the rear I believe are the same diameter between the years.
    Last edited: Oct 25, 2017
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  7. BrianTrick

    BrianTrick Brian Trick

    He can reuse his existing brakes and hardware.
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  8. wkillgs

    wkillgs Gold Level Contributor

    You might be able to swap the 65 brake junction block to the 68 rear and keep the 65 style hose. Get a new hose while you're under there.

    Some rear brake hoses have the junction block as part of the hose, such as 67 Skylark. I think the 65 and 68 are the hose only, junction block is on the rear.

    Swapping the whole 65 brake assembly to the 68 rear is obviously more work. The 68 rear uses c-clips to retain the axles, so the cover has to be removed and the cross shaft removed to get the clips out.
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  9. BrianTrick

    BrianTrick Brian Trick

    If you want to reuse the backing plates,and not interrupt the lines & fluid,yes,you would have to pull the clips,but all of his hardware will transfer to the Chevy backing plates. You would just have to rebleed the brakes.
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  10. monzaz

    monzaz Jim

    Why would you not just get your original rear built? Buy the posi gears etc ... Why put the Chevy rear in the Buick...PLUS you know the rear is a good runner to rebuild as it is in good working order already.

    Just more thoughts before you toss out the proper rear for the car. You can make ANY rear posi and any ratio there is not a limit in that.

    U-joints - all the chain stores have the conversion joints especially the chevy to BOP which is 1310 to Mechanic3R joint 1330 is the chevy large big block u-joint. which uses snap ring ends. BOP uses the inside c-clips that are pressed into a grooved cap 1 1/8" diameter.


    Step 1: Does your U-Joint take inside or outside snap rings?
    Step 2: What is the cap diameter of the U-joint?
    Step 3: What is the breadth of the U-joint?

    U-Joint #





    Snap Rings





    Cap Diameter
    1.063 in

    1.063 in

    1.188 in

    1.188 in

    1.125 in

    3.219 in

    3.622 in

    3.622 in

    4.187 in

    2.556 in**

    Good luck, Jim
    J D
  11. robert v

    robert v Well-Known Member

    Thank You for replying and for the information.
    My 1965 is a survivor and I want to keep it original to Buick.

    I will have the original uint built.
    Can someone advise / recommend a shop (Long Island, New York).

    Thank You,
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  12. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD"

    Freddy Brown


    That is where I had my 8.5 10 bolt rear built.
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  13. robert v

    robert v Well-Known Member

    Thanks for the info.
    I will call them on Monday.
    They are located within 30 miles of my house.
  14. Donuts & Peelouts

    Donuts & Peelouts Life's 2 Short. Live like it.

    Very informative thread

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