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Thread: 5.3 heads on a 6.0

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  1. #1
    Join Date
    Aug 2007
    Location
    Needville,TX
    Posts
    433

    5.3 heads on a 6.0

    I bought a set of 05' 6.0 cylinder heads on ebay with only like 1500 mile on them. Got them and put them on then I noticed the casting # is 706 which is an 04 and up 4.8/5.3 head. Boy was I pissed because I should have ck'd but I believed they were 6.0 heads and this guys auction claimed it came off an 05' chevy 2500 truck.

    Now Im wondering if this will cause any problems and if it does what will be the problems.
    I contacted the ebay member just a few min ago and we'll c if he even knows..or responds!!
    Damnit if aint one thing it sthe next.
    89' GMC RCSB 6.0L LQ4, T56, 4.56 Gears

  2. #2
    Join Date
    Dec 2006
    Posts
    4,033
    i have 706 casting 5.3 heads that are ported and polished on my lq9 i used these heads to raise the cr which is now just above 11:1 maybe 11:5:1 i dont know foresure but i do know its up there..
    Simple: 408 on steroids!
    single digits coming soon!

  3. #3
    ff_jeff Guest
    hey skeet, do you run 93 gas in your motor? and have you dyno'ed it?

  4. #4
    Join Date
    Dec 2006
    Posts
    4,033
    Quote Originally Posted by vff_jeff View Post
    hey skeet, do you run 93 gas in your motor? and have you dyno'ed it?
    yes i run 93 octane, nelson performance tune

    been having some seriuos tranny issues, hoping that it has been resolved when the new tune gets here, the issues were elecetrical at first then went into a total rebuild of the tranny, without going into detail i had them hook a manual pressure guage to the tranny and the pressure was like 230 psi way to high, and it wasnt controlable, so i ordered a updated tune hoping this solves the problems with the pressure ... but anyway once i get it right once again i plan on dynoing it right off the bat just to see where i sit with it rwhp and tq wise..

    on another note getting nother pcm may aliviate the pcm from being bad.. i really dont know, but will find out soon kros


    sorry for whoring your thread
    Simple: 408 on steroids!
    single digits coming soon!

  5. #5
    Join Date
    Aug 2007
    Location
    Needville,TX
    Posts
    433
    So bolting these heads on stock shouldnt be a problem?

    What is the CC of the 706 heads. I thought they where the same as the 317 heads???
    89' GMC RCSB 6.0L LQ4, T56, 4.56 Gears

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