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What does it take to put an 8.5 into a 7.5 car?

Discussion in 'General Discussion' started by MrSony, Oct 11, 2017.

  1. pontiacgp

    pontiacgp Canadian Prime Minister

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    the other thing is to get an old shaft cut and balanced is only about $80 cheaper than getting a new shaft using your old yokes. When you get your shaft back after it's balance make sure you mark the front yoke so if you ever remove the u joint you don't put it back on out of phase.
     
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  2. Turbo Zach

    Turbo Zach G-Body Guru

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    I got the guy I bought mine from to throw the GN drive shaft in the deal. I replaced the u joints with good brand name ones. When my car starts making power I plan to have a cromemolly shaft made. I would not trust factory very far! As for the swap. Direct swap.only thing was the 8.5 came with metric studs and the Monte had standard.
     
  3. 64nailhead

    64nailhead Master Mechanic

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    I believe 80 was the cutoff from standard to metric, but lugnuts are cheap - lol.
     
  4. oldsmobile joe

    oldsmobile joe Master Mechanic

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    you can always replace the front rotors with ones that have metric studs in them. cheaper than buying metric studs.
    joe
     
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  5. Turbo Zach

    Turbo Zach G-Body Guru

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    I am not too worried about it, but good to know.
     
  6. pagrunt

    pagrunt G-Body Guru

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    For the lug nuts remember A bodys have inch studs ('78-'81) & G bodys have metric studs ('82-'88). This way you'll know what rotors to match the rear end axles. Side note, you '78 owners would need to swap in '79 up spindles or go with the Blazer conversion for metric studs.
     
  7. pontiacgp

    pontiacgp Canadian Prime Minister

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    don't the 78 to 80 G bodies have the small outside bearings on the spindles?
     
  8. 84GP455

    84GP455 G-Body Guru

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    For my swap 7.5 to GN 8.5 it was fairly easy I did have to cut the shaft 1 inch but that's because I also swapped the th400 for the GN th2004-R as far as the 8,5 goes.. the best ones are out of the Grand Nationals and 442
     
  9. oldsmobile joe

    oldsmobile joe Master Mechanic

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    Iirc, only on the 78my.
    Joe
     
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