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4L80E cross member

Discussion in 'The Garage' started by muddybuddy, Nov 7, 2006.

  1. muddybuddy

    muddybuddy 3/4 ton status

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    im still piecing together all my parts for my swap, and i was wondering if there was a stock cross-member out there that would work for 4L80E. i know they came in '91 cc's and maybe some burbans, would one off of one of those work on my 88 k5?
     
  2. Jimbo*

    Jimbo* 1/2 ton status

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    Where do you intend to attach this crossmenber to the 4L80? Unless I am mistaken, you are putting a modified TH400/NP203 adapter plate behind the 4L80; therefore, you will need to put a NP203 crossmember under the adapter.
    This is to say there won't be room for or an attachment point for the stock 4L80 crossmember.
    Jimbo
     
  3. muddybuddy

    muddybuddy 3/4 ton status

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    so i would just need a cross-member for a 203? did they ever use 203's once they changed frames in 81? that way i could use a stock one.
     
  4. Jimbo*

    Jimbo* 1/2 ton status

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    Sorry to sound condescending in my first reply.
    The crossmember you need would be from a K10 or K20 from 1973 up through about 1984--basically any "tall adapter" cross member not from a 1-ton. If you have trouble finding one, let me know and I'll hook you up.
    Jimbo
     
  5. muddybuddy

    muddybuddy 3/4 ton status

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    wouldnt it need to be after '81 tho, since the frame changed? so basically a cross-member from any k10,k20 that had a 203 t-case right? thanks for the replies jimbo

    damn jus looks in the specs, and they didnt use the 203 after '80 so i guess i gatta use an older one and fab it to work.
     
  6. 79k20350

    79k20350 3/4 ton status

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    I dont belive the frames changed that much. any 203 crossmember should work
     
  7. 1979jimmy350

    1979jimmy350 1/2 ton status

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    the change in the frames in the 80s was only on the front the crossmember are never changed from 73 up
     
  8. muddybuddy

    muddybuddy 3/4 ton status

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    alright cool. thanks for clearing that up. :)
     
  9. neverendingproject

    neverendingproject 1/2 ton status

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    Im making my own. I dont have a doubler, but I will be able to jack the truck up on mine if I want. :D:D:D:D
     
  10. muddybuddy

    muddybuddy 3/4 ton status

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    i will probably eventually get my friend with a welder to fab up a complete cross-member, but right now i aint got access to welder:doah:
     
  11. dyeager535

    dyeager535 1 ton status Premium Member

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    I tried to put an older crossmember under my '81 frame and it wouldn't work.

    I suspect the length of the drivetrain assembly is what matters, any of the 465 combos I assume put the crossmember forward further, and the frame simply wasn't wide enough on the '81 for the older crossmember to bolt up. the two front bolts were at the outside edge of the frame.
     
  12. u2slow

    u2slow 1/2 ton status

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    How about you use the existing crossmember? I think that's the best one for the job. Its most likely identical to the one that would have come in a '91 Burb.

    ;)
     

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