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Looking for info on engine swap

Discussion in 'The Garage' started by EastTexasBlazer, Apr 30, 2007.

  1. EastTexasBlazer

    EastTexasBlazer Newbie

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    I have a 1980 K-5 Blazer with a tired 350 small block and 350 turbo trans. I just recevied a good running 454 big block and turbo 400 trans out of a 2x 1974 Suburan. I curently run a np205 transfer case behind my turbo 350 does anyone know if it will mount up or do I have to change input shaft to run the 400. And does anybody know if I will run in to problems with the install of the 454. You can send to me at easttexrednex@hotmail.com thank you.
     
  2. Kp

    Kp 1/2 ton status

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    I have an '83 k2500 sub that was originally a 350 truck according to the VIN.
    Before I got it, someone had swapped in a 454. I killed that motor, and put a rebuilt 454 in there. The mounts appeared to be original, and the only modification I found was that the exhaust manifold was ground down to clear the framrail. Other than that, I didn't see anything that was altered. I think that would've been unneccessary with taller motor mounts.
    I am not sure if all of the 350 accessories will bolt to the 454, but as far as I could tell, the swap itself was almost bolt-in.
     
  3. 85mudbogger

    85mudbogger 1/2 ton status

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    just put the 454 up to the 350th and get some bbc headers
     
  4. dremu

    dremu Officious Thread Derailer Premium Member

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    I don't know if motor mounts are the same for a 350 and 454; the frames are the same, though the 2WD's have a different crossmember.

    The TH350 won't hold up behind a big block for long.

    Your NP205 won't bolt up to the TH400, as the TH350 has 27 splines and the TH400 is 32. So yeah, you'll need to switch input shafts on the transfer case.

    Also a potential issue is that the output shaft on the tranny -- once you remove the yoke -- may be the wrong length to fit into the t-case. I've heard varying stories about interchangeability of these.

    That said, I'd still make the TH400/205 combo work as it's bulletproof, MUCH stouter than a TH350.


    -- A
     
  5. sweetk30

    sweetk30 professional hooker Premium Member

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    i know guys who reman the th350 with good parts and extra clutches and thay hold up just fine on stock or mild built 454s. and as to motor mounts yes bbc has taller mounts but not by much. sbc stuff will work just fine for mounts lots of guys do it.

    and get all the bbc stuff you can for the swap.
     
  6. BadBob

    BadBob 1/2 ton status

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    I can tell you one thing you might run into:

    Some headers won't clear the oil filter if you keep the OEM oil cooler/adapter on the big block.
     
  7. pauly383

    pauly383 Daddy383 Staff Member Moderator

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    The motor mounts on the block should go right over the frame mounts IIRC
     

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