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Thread: 2009 5.3 heads

  1. #1
    Join Date
    May 2004
    Posts
    2,120

    2009 5.3 heads

    What heads do you have on your 5.3? I just happened to look at my 09 Tahoe and it has 243 castings. This is the first time I've seen these on a 5.3 but that's just me. Who else has 243's on their 5.3?


    97 GMC, 2002 LS6.

    1991 GMC Syclone #1428

  2. #2
    Join Date
    Sep 2008
    Location
    Hope Mills, NC
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    676
    i got em on my 07 5.3.... any 5.3 07+ will have either 799 or 243 casting. they are identical heads just different numbers. flow the same just a different stamping. The motor also has 9:9.1 compression and the intake flows the same as an ls6 if you really wanna get into it.
    2005 GMC RST *sold
    2006 Silverado SS with nawz

  3. #3
    Join Date
    May 2004
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    2,120
    Thanks for the info. I knew the flow was the same just didn't realize gm put the 243's on the 5.3's. I better look at the driver side because I remember GTO's and vettes with 1 - 799 head and 1 - 243 head on the other side. My LS6 has 10.5:1 with 243's and I love it. The 09' has great response also eventhough I haven't tuned it yet.


    97 GMC, 2002 LS6.

    1991 GMC Syclone #1428

  4. #4
    Join Date
    Sep 2006
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    THE 405
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    They're 243s but they have different valves in them or something. I forget what the deal is
    2007 RCSB|DTR81 built LSx 3xx|PRC|NX|BOGART|MSD|QUICKFUEL 950 E85|4L80|FTI Converters|Smith RaceCraft|Racepak
    midweststreetcars.com

  5. #5
    Join Date
    May 2004
    Posts
    2,120
    Yes Parker, from what I've read on LS1Tech the truck 243 heads have stock LS1 valves, LS6 valave springs and the same machine work as the LS6 heads. I remember reading about this awhile back and just forgot. Man how time fly's!


    97 GMC, 2002 LS6.

    1991 GMC Syclone #1428

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