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Thread: 5.3 in OBS

  1. #1
    Join Date
    Feb 2008
    Posts
    3

    5.3 in OBS

    how hard is it to swap? which would be best, buying a factory replacement tbi 350 or this motor? i found what seems to be a very good deal...everything, 5.3L motor, 4l60e tranny, wiring harness, all accessories for 3000 obo. 40 thousand miles out of an 04 silverado. seem liike a good idea?

  2. #2
    Join Date
    Oct 2005
    Posts
    147
    Exchanging the 5.3 will be a little more work, but my experience has been that it is a lot more fun when you are finished.
    There are a lot of go fast parts available, and generally they are very good engines.
    Look around this site and you should find all the answers to the swap
    '92 Fullsize, swb rc
    5.3L/T56 conversion, comp XR275 HR cam .566/.568 lift 222/224 duration 112 lsa, crane dual springs, trick flow push rods, K&N Filter, Nelson Performance tune, Keisler shifter relocation kit, Boyd Coddington Smoothie II 18x8 235/55 up front, 18x10 295/45 out back, 2/4 drop, eaton lsd w/4.56 gears

  3. #3
    This topic is the only reason I came searching for a site for trucks with these motors. I have a 98 OBS 4.3 truck and I just purchased a 5.3 03 motor and harness for it. I just need help on the wiring of the harness, and some misc other things.

    Help would be great

  4. #4
    Join Date
    Oct 2005
    Posts
    147
    My short answer for wiring is to let Nelson performance either make a custom harness, which are very very nice, or have them rework your existing harness.
    I had them rework mine, and the installation was very smooth.
    Great guys to work with, and their work is second to none.
    '92 Fullsize, swb rc
    5.3L/T56 conversion, comp XR275 HR cam .566/.568 lift 222/224 duration 112 lsa, crane dual springs, trick flow push rods, K&N Filter, Nelson Performance tune, Keisler shifter relocation kit, Boyd Coddington Smoothie II 18x8 235/55 up front, 18x10 295/45 out back, 2/4 drop, eaton lsd w/4.56 gears

  5. #5
    Join Date
    Jun 2007
    Location
    maine
    Posts
    1,458
    pat is the man! hes pretty much walked me through a lot of it so far! good source of info! im doing a 02 5.3 in my 98 4.3 obs
    09 CREWCAB LTZ SILVERADO, 6.2, SIX SPEED, CAI,

  6. #6
    Join Date
    Oct 2005
    Posts
    147
    I just try to keep up.
    Keep asking, though there is a lot of knowledge on this board.
    '92 Fullsize, swb rc
    5.3L/T56 conversion, comp XR275 HR cam .566/.568 lift 222/224 duration 112 lsa, crane dual springs, trick flow push rods, K&N Filter, Nelson Performance tune, Keisler shifter relocation kit, Boyd Coddington Smoothie II 18x8 235/55 up front, 18x10 295/45 out back, 2/4 drop, eaton lsd w/4.56 gears

  7. #7
    what does he usually charge for the harness re work?

  8. #8
    Join Date
    Oct 2005
    Posts
    147
    Quote Originally Posted by hellfire_studios View Post
    what does he usually charge for the harness re work?

    It has been a couple years since I had mine done, but I think it was around 250-300 dollars.
    Call NelsonPerformance as the prices may have changed.
    his custom harness is very nice.
    '92 Fullsize, swb rc
    5.3L/T56 conversion, comp XR275 HR cam .566/.568 lift 222/224 duration 112 lsa, crane dual springs, trick flow push rods, K&N Filter, Nelson Performance tune, Keisler shifter relocation kit, Boyd Coddington Smoothie II 18x8 235/55 up front, 18x10 295/45 out back, 2/4 drop, eaton lsd w/4.56 gears

  9. #9
    Join Date
    Oct 2005
    Location
    Baton Rouge, LA
    Posts
    997
    I think the harness prices are higher than that, but call him up to verify. As for $3K, where are you getting this from (Salvage or what)? Seems like I ran across similar setups with about 10K more miles for ~$500 to ~$1000 or so less. Shipping costs might make the difference... depends on locale, I guess.
    Test-n-Tune (Nov 23, 2008) - 13.65s @ 98mph

  10. #10
    Join Date
    Apr 2007
    Location
    Utah
    Posts
    71
    The wire harness rework is like $450.00 or thereabouts which is well worth it. I paid $650.0 from vendor in Florida to make my harness and he messed up a bunch of things like TCC command, Cylinder 6 & 8, trans temp low,and Alternator charge. I had to pull my harness and send it to a reputable vendor to get it working properly. and it took 6 months of diagnosis before we were sure the poor running of the engine was due to these problems.

    Do the harness right the first time. It really is worth it!
    1990 K2500 with Hummer Kit Body, LQ4, 4l80e 4x4

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