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400 chevy swap

Discussion in 'The Garage' started by chvymudin3388, Jan 13, 2006.

  1. chvymudin3388

    chvymudin3388 1/2 ton status

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    is a chevy 400 a small block or a big block not to sure if it is a small block can i swap it with my 350 and are all the componets the same like intake and manifold and all
     
  2. darenofears

    darenofears Registered Member

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    reply

    it is a small block
    but i am not sure about the components swapping
     
  3. Leper

    Leper 1/2 ton status

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    This weekend I am replacing a 350 with a 400. The flexplate on the 400 is different. IIRC the 350 and 400, externally, are the same. I don't know if the intakes are interchangable, but if you are swapping one for the other there is no problem as long as you have the 400 flexplate.
     
  4. koldsimer

    koldsimer 1/2 ton status GMOTM Winner

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    Yup, the only other thing is the dampener. I think that they are different also. Intakes are interchangeable as are all accesories.
     
  5. Muddytazz

    Muddytazz 1 ton status

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    the flexplate/flywheel and the front dampener are the only things on the outside of the motor that are different. All other external stuff will swap over from 350 and 400. Internal stuff on the otherhand is different.
     
  6. sweetk30

    sweetk30 professional hooker Premium Member

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    most likly not but make sure its not a 402 bbc. some people might get them mixed up. thay look like a big block as thay are. just 402 cid. if the exaust ports are sistered in the heads in the middle 2 then small block. if all 4 seperate then big block. but likly not.

    and as listed before dampener and flex/flywheel diffrent on 400 sbc.
     
  7. u2slow

    u2slow 1/2 ton status

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    When the 69-72 trucks got a '400' it was actually a 402ci bbc (396ci + 0.030" factory overbore).

    A couple other snags you might run into for 350 vs. 400 sbc is the heads. 86+ sbc heads & intake have a different angle on the center intake bolts. 400sbc heads have steam holes - essential cooling feature for the siamese-bore 400 block. (Other sbc heads can be drilled, but cracking afterwards can be problem with some of the lighter castings.)
     
  8. muscle

    muscle 1/2 ton status

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    400 is externally balanced. you will need flexplate, balancer. Intake from the 350 will swap over. same with brackets, pulleys etc.

    have fun :laugh:
     
  9. chvymudin3388

    chvymudin3388 1/2 ton status

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    the 400 im lookin at is in a 79 chevy truck so does ne body if its the 402 bbc or 400 sbc?
     
  10. u2slow

    u2slow 1/2 ton status

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  11. Clod_King

    Clod_King 1/2 ton status

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    as I understand it, the 305, 350, 400 are all based on the same block, and the major difference is in the stroke.
     
  12. 1977k5

    1977k5 3/4 ton status Vendor

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    The 400 block is very different from the others. It has siamesed cylinders along with a different cooling design.
     
  13. beater_k20

    beater_k20 Banned

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    not true, the 400 SBC was introduced in 1970. i have seen several "400" fender emblems, open the hood, find a 400 small block.
     
  14. u2slow

    u2slow 1/2 ton status

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  15. Clod_King

    Clod_King 1/2 ton status

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    what are "siamesed cylinders"?
     
  16. u2slow

    u2slow 1/2 ton status

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    The block is cast without cooling passages between the cylinders - to ensure enough cylinder wall thickness with the 4-1/8" bores.
     
  17. Leper

    Leper 1/2 ton status

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    My 350 to 400 swap ended up being a 305 to 400 swap. The starters are different.
     

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