Discussion in 'Trucks and Trailers' started by RTallday, May 14, 2001.

  1. RTallday

    RTallday LawnSite Member
    Messages: 214

    I have a question regarding engine swapping. What has to be changed in a 79 k-20 to change it from a small block to a big block? Thanks for the help.

  2. MTCK

    MTCK LawnSite Senior Member
    from Idaho
    Messages: 254

    I believe the bellhousings are the same. You'll need new motor mounts though I think. More cubes are good. Go with it.

  3. 75

    75 LawnSite Senior Member
    Messages: 992

    Not 100% sure here, but I think a cooling system upgrade (from a 3-core to a 4-core radiator) may also be necessary.
  4. Pauls Mowing

    Pauls Mowing LawnSite Member
    Messages: 207

    Let me know what happens Rich, I'm thinking of going in the other direction with my '92 C-3500 dump truck, 454 to a 350.

  5. 4x4k20

    4x4k20 LawnSite Member
    from ga
    Messages: 148

    i had one 79 k20 that i did this too you will need big block ehxt. manifolds all the big block brackets for alt ps air you will need a differet flywheel the big blocks are external balance the bellhousing is the same you use the same motor mounts will need a bigger rad. the fuel pump will have to be one for a big block 4x4 if yours is a 4x4 they are a little shorter i cant remember everthing but it is not hard to do i wished i would have never sold that truck it was a hoss but dont look for good gas mileage
  6. RTallday

    RTallday LawnSite Member
    Messages: 214

    Thanks for the responses guys. Also, the transmission, will it bolt up with no adapters? I have the 4 speed granny gear trans. I believe i already have the 4 core radiator. Im glad all i have to change is the motor mounts and all the little stuff. No big deal really. Thanks.
  7. RTallday

    RTallday LawnSite Member
    Messages: 214

    Also, The reason i ask, is because at the machine shop right now is my 1968 427 block. Hope to build a crazy motor, move that truck a little quicker!!

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