8" or 9"

Discussion in 'Parts Interchange' started by AERDAVID, Nov 27, 2011.

  1. AERDAVID

    AERDAVID Member

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    Greetings, looking for experience on 8" rears in the Mavs. I am building a 429 car and wonder if the 8" will stand up to my 450 hp 429? or should I be looking for a 9". Thanks
     
  2. rthomas771

    rthomas771 Member

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    The 8" is good to about 300 hp. A factory 9" can't take 450hp. With that much hp you need an aftermarket setup
     
  3. don graham

    don graham MCG State Rep

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    I'd opt for the 9" with aftermarket gears and axles. :)
     
  4. AERDAVID

    AERDAVID Member

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    9" it is ! Junk yoards here I come. Thanks
     
  5. don graham

    don graham MCG State Rep

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    good luck. Most 9" rears are too wide and you'll have to get them narrowed. The best are the ones from a 57 Ford ranchero or Wagon. They are a direct bolt in. They were also in some Mustangs, but they are big bucks. Then there also are some in the Grenada cars that are a little wide but can be compensated by more backspacing. Do a search on here and all the back threads on 9" rears will come up.:)
     
  6. AERDAVID

    AERDAVID Member

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    You are right there, I had done some interesting reading, a tech article back from 2007 on this forum by a name "Mavaholic" I found it to be something I would try it was labeled something like "poor mans guide to narrowing" or something like that, it was a really cool idea.
     
  7. rthomas771

    rthomas771 Member

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    A factory housing ain't gonna stand up to 450 hp. The tubes are too thin and will twist at the spring perch.
     
  8. Joe Dirt

    Joe Dirt BBF life

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    Speedway motors sells a 56.5" 9" ford housing and axle kit. Fwiw and its affordable

    Same width as the stock maverick rear
     
  9. Joe Dirt

    Joe Dirt BBF life

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  10. AERDAVID

    AERDAVID Member

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    I am trying to find the tube thickness and can't anywhere, guess I need to ask or do you know. Thanks.
     
  11. Joe Dirt

    Joe Dirt BBF life

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    most currie housings have .188 thick tubes

    at 450 h/p i doubt you will have a problem with axle tubes jmho
     
  12. AERDAVID

    AERDAVID Member

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    And thanks for the link, I need all the help I can get.
     
  13. Joe Dirt

    Joe Dirt BBF life

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    I seen them the other day and thought for the money it was a great deal.
     
  14. Bryant

    Bryant forgot more than learned

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    the problem with that housing is that the pinion off set is 2 3/8" to the passenger side. this may cause the drive shaft to rub on the passenger side of the tunnel. some people have put and explorer 8.8 which has a similar pinion offset as this 9" does and not have a problem with a stock drive shaft. they say its very close. you may want to go under your car and undo the drive shaft from the current diff and move it over 2.5 inches and move it up and down and see if it will clear. the 9" does lower the yoke about another inch in the car than the 8" also.
     
  15. TJC47

    TJC47 Member

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    nine inch

    I replaced the 8" in my 64 Fairlane with a 8.75 " out of a 57 Fairlane and I understand that the 9" gears will fit. I had the spring perches relocated.
     
    Last edited: Dec 1, 2011

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