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4.8 build

Discussion in 'GM Powertrain' started by kountrykid, Oct 3, 2011.

  1. kountrykid

    kountrykid New Member

    So here is the deal. I have a 2004 ext cab Z-71 with a 4.8. I recently picked up a 5.3 that needs some work CHEAP. Everything I've read and everyone I've talked to says the only difference between a 4.8 and 5.3 is the stroke (correct me if I'm wrong). Anyways I have been doing some reading about the crank swap from my 4.8 to the 5.3. Would I have to upgrade anything else to do this? I know I would have to get a crank case relearn for it to run and get my ECM reprogrammed. All I need to know is if I would have to do anything else. Also I've seen a lot about LS1 cam swaps in the 4.8 and 5.3s. Would I be able to have more of a HP gain with the 4.8 or the 5.3? I'm planning on getting a custom tune with all of this to really set it free. Any additional info and input would be GREAT. Thanks for reading

  2. nos351wcm

    nos351wcm Rockstar

    Yeah the only difference between the 4.8 and the 5.3 is the stroke. The 5.3 also has different pistons and connecting rods. If you swap the crank you will also have to swap your pistons and connecting rods.
    The 5.3 and 4.8 depending on year, put out close to the same amount of horsepower, but the 5.3 produces more torque.
    Also, any parts that can bolt onto an ls1 will bolt onto the 4.8/5.3/6.0 engines.

    Hope this helps and goodluck
  3. silveradotrailblazer

    silveradotrailblazer Epic Member 5+ Years ROTM Winner 5000 Posts

    Welcome to the club. Why not rebuild the 5.3? If you bore the 5.3 from 96mm to 99mm and use the 5.3 crank you have a 5.7. Change the intake valves from 1.89 to 2.00 and install the LS1 cam (the same came used in the LQ4 and LQ9 6.0's) you basicly have a cast iron block LS1.

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