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Rear end Question?

Discussion in 'The Garage' started by jackh, Dec 16, 2003.

  1. jackh

    jackh Registered Member

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    I am running the stock 10 bolt rearend in my 86 K5 Blazer and was wondering how or what rearend I could go to that would better hold up to the 425hp/512 ftlb torque.

    Note ! This Blazer will never be used off road, it currently has 265-75-15 street tires on it. These tires do make alot of noise during a WOT start. But I cringe every time /forums/images/graemlins/confused.gif, thinking this is the time the rearend will give up.

    I am currently out of money for this project so I need to upgrade the rearend for as cheap as possible. Please HELP.

    Thanks,,,,,Jack
     
  2. Z3PR

    Z3PR Banned

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    [ QUOTE ]
    I am running the stock 10 bolt rearend in my 86 K5 Blazer and was wondering how or what rearend I could go to that would better hold up to the 425hp/512 ftlb torque.

    Note ! This Blazer will never be used off road, it currently has 265-75-15 street tires on it. These tires do make alot of noise during a WOT start. But I cringe every time /forums/images/graemlins/confused.gif, thinking this is the time the rearend will give up.

    I am currently out of money for this project so I need to upgrade the rearend for as cheap as possible. Please HELP.

    Thanks,,,,,Jack


    [/ QUOTE ] In my honest opinion, you can't get any better then a 14 bolt FF for a rear axle, and they're fairly cheap too. /forums/images/graemlins/thumb.gif Then use the 8 to 6 lug adaptors so you can keep the same rims. Just make sure the gears match the front.
     
  3. K5MONSTERCHEV

    K5MONSTERCHEV 1/2 ton status

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    Atleast put in a 12 bolt. I just built one the other day for a Chevelle with a 502, there pretty good rearends.
     
  4. rjfguitar

    rjfguitar 3/4 ton status GMOTM Winner

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    [ QUOTE ]
    Atleast put in a 12 bolt. I just built one the other day for a Chevelle with a 502, there pretty good rearends.

    [/ QUOTE ] A car 12 bolt is a different rearend than the familiar truck 12 bolt. And I don't think a 12bolt is enough anyway. If you keep that tire size I would look for a 14BSF or FF.
     
  5. Silver84k5

    Silver84k5 1/2 ton status

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    i dunno whats the purpose of having such a nice engine in a stock rig thatll never see the Dirt,unless your interested in Drag racin... If thats the case, Then think about putting a ford 9 inch in there, if you dont care about using a ford part. Less weight then the 14ff. Plus its Fairly strong.
     
  6. rjfguitar

    rjfguitar 3/4 ton status GMOTM Winner

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    I second the ford 9" but I would prefer a 14BSF with 6 lug axles. It would be bolt in for the most part and be plenty strong.
     
  7. jackh

    jackh Registered Member

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    What's a 14BSF or FF? /forums/images/graemlins/confused.gif Are these rearends out of trucks, What kind? Can I find one at a junk yard? I'ed like to stay with the 6 lug without needing an adapter.

    Thanks,,,,Jack
     
  8. rjfguitar

    rjfguitar 3/4 ton status GMOTM Winner

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    GM made to different rearends that are called " 14b". The 14bolt Full floater (the big one) is a 10.5" ring gear rearend with full floating axles and hubs, only came in an 8 lug version. It was put in 3/4ton HD and 1 ton pickups, vans, and 3/4HD suburbans. With this axle you get your pie and eat it too because it is one of the best HD rearends that is great for offroad use and to top it off they are plentifull and cheap! It will handle up to 44" tires with some serious HP no problem./forums/images/graemlins/thumb.gif

    The second one is the 14bolt semi floater or "metric" 14B, it's the "small one". It wasn't made until the 80's but is a decent rearend for medium duty applications. It has a smaller 9.5" ring gear than it's big brother and came in both 6&8 lug versions. It comes from 3/4ton light duty and 1/2ton HD applications. This is a great upgrade from the weak 10 bolt that will handle some good HP along with oversized tires up to around 37" to 38". One to look for is a 90's 3/4ton light duty 6 lug 2wd truck.

    Both are great rearends that will last a long time and handle some serious abuse. I have a 14BFF and can attest along with many other guys that it is a bullet proof rearend. /forums/images/graemlins/smile.gif
     
  9. K5MONSTERCHEV

    K5MONSTERCHEV 1/2 ton status

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    [/ QUOTE ] A car 12 bolt is a different rearend than the familiar truck 12 bolt.

    [/ QUOTE ]

    I am aware of that. But I didnt think it is any weaker.
     
  10. jackh

    jackh Registered Member

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    [ QUOTE ]
    One to look for is a 90's 3/4ton light duty 6 lug 2wd truck

    [/ QUOTE ]

    Thanks for the info. Will start looking tomorrow. /forums/images/graemlins/smile.gif

    Later,,,,Jack
     
  11. big83chevy4x4

    big83chevy4x4 3/4 ton status

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    im not sure but, i dont think that the 14bsf came with 6 lug until 88. im also no sure on the width on the 88 and newer axles or the spring pad width. i do know that you can get aftermarket 6 lub axles for about 100 each to fit the older 14bsf
     
  12. rjfguitar

    rjfguitar 3/4 ton status GMOTM Winner

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    [ QUOTE ]
    im not sure but, i dont think that the 14bsf came with 6 lug until 88.

    [/ QUOTE ]
    You are correct.
    [ QUOTE ]
    im also no sure on the width on the 88 and newer axles or the spring pad width. i do know that you can get aftermarket 6 lub axles for about 100 each to fit the older 14bsf

    [/ QUOTE ]
    2wd 88 and later trucks have the same width as the older axles but the spring perches must be moved. The 4wd rearends are wider but I have heard that the later model 4wd rears are the same width as the front earlier strait axles, this would be nice for correcting the narrower rear trac width that our trucks have.
     
  13. Z3PR

    Z3PR Banned

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    [ QUOTE ]
    GM made to different rearends that are called " 14b". The 14bolt Full floater (the big one) is a 10.5" ring gear rearend with full floating axles and hubs, only came in an 8 lug version. It was put in 3/4ton HD and 1 ton pickups, vans, and 3/4HD suburbans. With this axle you get your pie and eat it too because it is one of the best HD rearends that is great for offroad use and to top it off they are plentifull and cheap! It will handle up to 44" tires with some serious HP no problem./forums/images/graemlins/thumb.gif

    The second one is the 14bolt semi floater or "metric" 14B, it's the "small one". It wasn't made until the 80's but is a decent rearend for medium duty applications. It has a smaller 9.5" ring gear than it's big brother and came in both 6&8 lug versions. It comes from 3/4ton light duty and 1/2ton HD applications. This is a great upgrade from the weak 10 bolt that will handle some good HP along with oversized tires up to around 37" to 38". One to look for is a 90's 3/4ton light duty 6 lug 2wd truck.

    Both are great rearends that will last a long time and handle some serious abuse. I have a 14BFF and can attest along with many other guys that it is a bullet proof rearend. /forums/images/graemlins/smile.gif

    [/ QUOTE ] I like the FF becouse there is no "C" clip. If you do break a axle shaft, you can still drive it home, as where the SF your tire will be laying on the grounds and so will that corner of your truck. /forums/images/graemlins/frown.gif
     
  14. Beast388

    Beast388 1/2 ton status

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    [ QUOTE ]
    [ QUOTE ]
    A car 12 bolt is a different rearend than the familiar truck 12 bolt.

    [/ QUOTE ]

    I am aware of that. But I didnt think it is any weaker.

    [/ QUOTE ]

    Just an FYI....as strange as it may seem, the car 12B is stronger than the truck 12B. The car's pinion stem diameter is 1-5/8" whereas the truck's is 1-7/16". The carriers are a little beefier on the car's too. /forums/images/graemlins/eek.gif /forums/images/graemlins/thumb.gif
     
  15. rjfguitar

    rjfguitar 3/4 ton status GMOTM Winner

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    [ QUOTE ]
    [ QUOTE ]
    [ QUOTE ]
    A car 12 bolt is a different rearend than the familiar truck 12 bolt.

    [/ QUOTE ]

    I am aware of that. But I didnt think it is any weaker.

    [/ QUOTE ]

    Just an FYI....as strange as it may seem, the car 12B is stronger than the truck 12B. The car's pinion stem diameter is 1-5/8" whereas the truck's is 1-7/16". The carriers are a little beefier on the car's too. /forums/images/graemlins/eek.gif /forums/images/graemlins/thumb.gif

    [/ QUOTE ]
    yep
     
  16. K5MONSTERCHEV

    K5MONSTERCHEV 1/2 ton status

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    Thank You, got it now!!
     
  17. 4x4Freak

    4x4Freak 1/2 ton status

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    The 6 lug is also fairly common in the Z71s. Not all of them got the 14 blt. I have noticed that most of them that did have it were pre 95, although I have seen a few later ones.
     
  18. zcarczar

    zcarczar 1/2 ton status

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    I run a 14 bolt Semifloater in the rear. I have broken it before, no it wasnt any thing internal in the diff. I broke the housing actually, I think I would have broken a FF rear end too because they both have the same tube thickness and diameter and I crushed both rear axle tubes. I love the rear end though, has more clearance than the FF and its just as strong for my app and it doesnt weigh 10,000 pounds either.
     
  19. R72K5

    R72K5 Banned

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    also ive noticed that at least the 95-up 10 bolts have two sets of leaf pads welded to the tubes,

    i dont know why though.
    i know for 95 4x4 shorty and for 98 Z71 at least, with 8.5" rear. was this started for 88-up ? or ?

    and yep car 12 bolt were made with a bit thicker parts,
    12 bolt truck seem to be weakest of all gm axles and most or all dana too. car 12 and truck 12 are two different worlds when it comes to parts interchangability, although you might be able to interchange diff cover bolts, maybe, haha
     

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