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Thread: wat to do with 243 heads?

  1. #1
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    wat to do with 243 heads?

    So i just bought a set of 243 heads and i was wondering if i should run them as is or have them worked a little bit (ported,polished, shaved etc.). I'm running a 220/220 .551 112 cam and ls6 intake but i dont want the heads to flow too much... and won't these heads stock lower my c/r since they have a larger combustion chamber? I haven't really dealt much with heads and what not so any advice is much appreciated!
    2008 GMC Sierra SLE....370ci LY6 with some goodies SOLD
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  2. #2
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    Yes they will drop your c.r. You'd have to shave .020-.030" off to get back to your stock c.r. if my numbers are correct. if your considering getting them ported I'd do it now, otherwise you'll regret it later. You can also look into a thinner head gasket to get some of that compression back

  3. #3
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    where did you happen to find the heads and how much did you get them for if you dont mind me asking. im on the search for a set myself.
    09 CREWCAB LTZ SILVERADO, 6.2, SIX SPEED, CAI,

  4. #4
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    on a 5.3, 243's will lower compression quite a bit. If you're staying N/A, i'd stick with worked 862's or some patriot heads
    blown transmissions are about as useful as 97% of the guys on this forum

  5. #5
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    i got a set of 799's from this place http://www.jakesperformance.com/Home_Page.html for $500. I don't see any engine parts on their page anymore but it might be worth a call

  6. #6
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    Quote Originally Posted by oleshifty View Post
    on a 5.3, 243's will lower compression quite a bit. If you're staying N/A, i'd stick with worked 862's or some patriot heads
    If you're paying to get your 862s worked, why not just pay for work on some 243s and have them milled and a 3 angle job? You'd spend a couple hundred more but you'd have much better flowing heads. They put 243s on the NNBS for a reason... they're nice.

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  7. #7
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    Get a port and polish job done on the 243's. Mill them 0.030 and have your compression back. Put a set of LS7 lifters in and use 7.40 pushrods. Done deal...

  8. #8
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    Quote Originally Posted by DBRODS View Post
    Get a port and polish job done on the 243's. Mill them 0.030 and have your compression back. Put a set of LS7 lifters in and use 7.40 pushrods. Done deal...
    Thx for that info bud!!! Thats my next step.
    RUN WAT U BRUNG!!!!

  9. #9
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    When i was looking into 243's....even milling down the max, the compression was still going to be lower then my stock 862's. Was the only reason i got a set of those worked/milled down to raise compression above stock.


    Lambo is running 862's and I THINK he's one of the fastest 5.3's. His guy is doing mine too. If the block was a 6.0, by all means, 243 will flow better. Sure most of you guys here know more then me, but few months ago I did tons of research and talked to a few machine shops, and they all agreed 243 would make me slower, and recommended working factory heads IF staying n/a. I went with a milder cam, so that could be part of the reason as well.
    blown transmissions are about as useful as 97% of the guys on this forum

  10. #10
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    i bought them off yellowsierra02 for $450. well i sure dont wanna spend all my money on a set of heads thats gonna make me slower...
    2008 GMC Sierra SLE....370ci LY6 with some goodies SOLD
    1995 C2500- LS1 swap with a mp112
    build thread- http://www.ls1truck.com/forums/lsx-t...-ls1-swap.html

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