LQ4 heads, cast iron vs. aluminum

Discussion in 'High Tech Retrofits' started by Paul1979, Sep 12, 2011.

  1. Air_Adam

    Air_Adam Veteran Member

    Messages:
    2,927
    Likes Received:
    0
    Joined:
    Feb 7, 2004
    Location:
    Saskatoon, SK, Canada
    What will the motor be used for though? The cathedral port heads will pretty easily support 500hp, so the extra cost of going to the rectangle port heads (which also means a new intake manifold, which ain't cheap) may not really pay off if the cathedral port heads can support the power he wants to make.
     
  2. mrvedit

    mrvedit Veteran Member

    Messages:
    1,355
    Likes Received:
    4
    Joined:
    Jun 12, 2009
    Location:
    Ann Arbor, MI
    Not bad advice, but just remember that will also require a new intake manifold, fuel rails and fuel injectors. The intake manifold will then require a bigger throttle body (aftermarket as all OE are drive-by-wire) which is then often combined with a new MAF and intake plumbing.
    I'm considering this upgrade from my LS2 with ported 243 heads, but the price is so high I am considering just buying an entire used LS3 engine.

    As always, these decisions depend upon your budget and expectations. If you are on a budget, I would still suggest aluminum heads. In a few years LS3/L92 parts should be more affordable. Just my 2 or 3 cents.
     
  3. mrvedit

    mrvedit Veteran Member

    Messages:
    1,355
    Likes Received:
    4
    Joined:
    Jun 12, 2009
    Location:
    Ann Arbor, MI
    Funny how Air Adam and I posted the same thing 40 seconds apart. This is a great forum with lots of activity and fast replies.
     
  4. Aceshigh

    Aceshigh Veteran Member Lifetime Gold Member

    Messages:
    26,757
    Likes Received:
    6
    Joined:
    Apr 9, 2001
    Location:
    Boondocks
    In the end, it all does depend on what the OP wants out of his car.
    He never specified if this was going to be carb'd or factory FI yet.

    I see spending $200 on exact same performance as a waste.
    The only thing he's saving is weight......

    For that amount it's not really noticeable on a cruiser IMO.
    Corner carving autocross or road race car, absolutely I'd consider it.

    Stock 317 heads flow.
    http://ls1tech.com/forums/10332813-post7.html

    Stock L92 heads flow.
    http://ls1tech.com/forums/4564757-post1.html

     
    Last edited: Sep 29, 2011
  5. Air_Adam

    Air_Adam Veteran Member

    Messages:
    2,927
    Likes Received:
    0
    Joined:
    Feb 7, 2004
    Location:
    Saskatoon, SK, Canada
    [​IMG]
     
  6. Camaro-Chevelle

    Camaro-Chevelle Veteran Member Lifetime Gold Member

    Messages:
    222
    Likes Received:
    2
    Joined:
    Sep 22, 2007
    Location:
    Long Island, New York
    What is the difference between 243 and 5364 cylinder heads?
     
  7. griffsbombelco

    griffsbombelco Veteran Member

    Messages:
    220
    Likes Received:
    0
    Joined:
    Aug 17, 2009
    Location:
    socal
  8. Leonards78LT

    Leonards78LT Veteran Member Lifetime Gold Member

    Messages:
    1,031
    Likes Received:
    0
    Joined:
    Jan 21, 2001
    Location:
    Central Oklahoma
    All the Gen III's with the exception of the 4.8L , used the same stroke crankshaft.
     
  9. griffsbombelco

    griffsbombelco Veteran Member

    Messages:
    220
    Likes Received:
    0
    Joined:
    Aug 17, 2009
    Location:
    socal
    It's not the stroke that's diff it's the flange the flex plate bolts to that's diff only used on all early steel headed 6.0s
     
  10. Camaro-Chevelle

    Camaro-Chevelle Veteran Member Lifetime Gold Member

    Messages:
    222
    Likes Received:
    2
    Joined:
    Sep 22, 2007
    Location:
    Long Island, New York
    I purchased a LY6 and 4L80 out of a 2009 Chevy Van. It comes complete with the wiring harness, TCM and all accessories. I am curious to see how good the cylinder heads are. Then I can make a decision on whether I need to upgrade the cylinder heads or not.
     

Share This Page

  1. This site uses cookies to help personalise content, tailor your experience and to keep you logged in if you register.
    By continuing to use this site, you are consenting to our use of cookies.