changing motors

Discussion in 'General Chevy & GM Tech Questions' started by rayandconnie, Mar 2, 2014.

  1. rayandconnie

    rayandconnie New Member

    We have 2 trucks that we would like to switch motors in. Will a 1999 5.3 Chevy Silvarado hook up without computer/electrical or other issues into a 2005 4.8 Chevy Silvarado? The 99 is pretty much worn out but the motor is very good while the 2005 is in good shape but we are losing oil pressure so would like to switch them if possible. The 5.3 also gets much better gas mileage! What issues would we run into while doing this? Thanks in advance for any help! Peace Connie
  2. Pikey

    Pikey Moderator Staff Member 5+ Years ROTM Winner 5000 Posts

    I believe that they are essentially the same motor on the outside. So, it should drop right in. Problems that you will run into are that the pre 2003 had an egr valve, the newer trucks do not. Also the in 2003 GM switched to drive by wire. So there is no cable going directly to the throttle body on your 2005 and on your 99 there is. If you switch the harness from your 1999 to your 2005 and the pcm it will remedy alot of the issues, but the drive by wire might be the hardest to overcome. you might be able to switch the throttle body from the 2005 to the 1999 5.3L and take care of the drive by wire issue. But, I don't know for sure. I am sure I missed something. someone else will come along to help.
  3. rayandconnie

    rayandconnie New Member

    Thank you so much for the info.. It was very helpful. Does anyone else have something to add before we get ourselves into a real pickle trying to switch motors?

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