Cummins swap into '96 z71

Discussion in 'GM Diesel & DuraMax' started by highmilageklr, Feb 19, 2009.

  1. highmilageklr

    highmilageklr Member

    Has anyone swapped a Cummins into a Chevy truck? Any info or links would be fantastic.
  2. phoebeisis

    phoebeisis Epic Member 5+ Years 1000 Posts

    Wish I could offer some knowledge, but.

    I have heard that the earlier ones-maybe even the 12 valve ones-got better mpg than the current ones.

    I guy who tows claims he gets 21 mpg unloaded- but with trailer- in his 1997 MT 3/4 ton Dodge 2wd.Pretty good mpg.

    I think the 2004's and earlier- 4 valve- are supposed to get better mpg than the more recent ones also.

  3. jchambers849

    jchambers849 Member

    recent cummins are powerful but not nearly as bulletproof or economical to run as the older cummins. With the horsepower race and new emissions laws came a loss in MPG and reliabiliy in the diesel truck world. I'm pretty sure of all the medium duty diesel trucks, the cummins gets the worst mpg.

    But who am I kidding, I would LOVE a cummins in my Z71.
  4. tlperry68

    tlperry68 Epic Member 5+ Years 1000 Posts

    I haven't seen it but that Cummins is a good motor.
  5. highmilageklr

    highmilageklr Member

    The reason I ask.

    This got 20.8 mpg from Omaha NE to Sioux City to Clear Lake Iowa to Des Moines Iowa to Shenandoah Iowa, last week end. Today from Malvern Iowa to Shenandoah Iowa, I got 27.8 mpg( all flat south bound). But it's still no Chevy....yet. I prefer my '96 z-71, but it only gets 14 mpg and 4 mpg with 10k trailer hooked! This gets 14-17 with the trailer, and will pull 80 mph uphill.[​IMG]
    Last edited: Feb 26, 2009
  6. High Voltage

    High Voltage New Member

    I had 2 Cummins trucks. My 24 valve actually did better than the 12v the way it was set up (best of 24 mpg hand calculated across Ohio).

    The engine is VERY heavy too, something to consider.

    I have seen 2 Chevy 1/2 tons and Jeep with 4BT Cummins engines, something to consider over a 6BT or 24 valve engine.

    I'd go '98 12 valve and older in the 6BT or do the 4BT for simplicity. Would help to stay away from the computer controlled 24valve engines.

  7. 2COR517

    2COR517 Epic Member 5+ Years 1000 Posts

    You would have to do some serious beefing of the frontend to carry the Cummins. Either a full swap from a K3500, or a Dana 60 SAS. I don't know about economy, but the Duramax has plenty of power, with more on tap.
  8. silveradotrailblazer

    silveradotrailblazer Epic Member 5+ Years ROTM Winner 5000 Posts

    Cummins swap into 96 Z-71

    Check out or phone them at 303-945-7570. They have Cummins conversions kit for Gms, Fords and Dodges.
  9. ChevyFarmKid

    ChevyFarmKid Rockstar


    I have seen a cummins swap into a mid 80's truck, but it was basic;y started from scratch. It turned out very well
  10. hmaster77

    hmaster77 Rockstar

    i would definitly go with a 12 valve bc they last forever i have helped swap out a 12 from dodge to another dodge and it wasnt to hard but it will b different to a z71

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