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??? LS1 Heads vs LS6 Heads ???

This is a discussion on ??? LS1 Heads vs LS6 Heads ??? within the Internal Engine forums, part of the LSx Technical Help Section category; 243 heads are the same casting..nothing really changed...243 from 01 on down will NOT have the lightweight valves..02+ 243 besides ...

  1. #41
    King 0f n00bz shady milkman's Avatar
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    243 heads are the same casting..nothing really changed...243 from 01 on down will NOT have the lightweight valves..02+ 243 besides ones found on the ls2 will have the lightweight vlaves and "higher lift springs" i believe they accept 500 lift...but besides that there is no difference in the 243..the 243s however are produced at several plants of which two(i believe) had a special casting process that allowed for VERY tight tolerances ..these are marked with the triangle ..but besides that nothing didnt on the castings..i personally will pick up some off a ls2..and get them worked ...since new springs and valves are in my plans anyways

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    Moderator Firebirdjones's Avatar
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    Quote Originally Posted by shady milkman View Post
    243 heads are the same casting..nothing really changed...243 from 01 on down will NOT have the lightweight valves..02+ 243 besides ones found on the ls2 will have the lightweight vlaves and "higher lift springs" i believe they accept 500 lift...but besides that there is no difference in the 243..the 243s however are produced at several plants of which two(i believe) had a special casting process that allowed for VERY tight tolerances ..these are marked with the triangle ..but besides that nothing didnt on the castings..i personally will pick up some off a ls2..and get them worked ...since new springs and valves are in my plans anyways
    I can't find any definitive information on the combustion chambers but either the pistons or the combustion chambers would have to be different on the LS2 cast 243 heads otherwise the compression would be 11:1 or more. And I do know these motors didn't have that much compression from the factory.....So where was the change made???? In the head or the piston??? I know on the 6.0 truck motors the change was made in the heads,,,to 71cc combustion chambers,,yet they also had the same port dimensions and D-shape exhaust port as the LS6's.

    Like I said, I wish I had a set of these later model 243's in my hand, I would love to poor the chambers and see where they are.

    As far as the castings and the triangular marks, that goes for all heads, I have a set of 241's like that as well.

  3. #43
    King 0f n00bz shady milkman's Avatar
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    Quote Originally Posted by Firebirdjones View Post
    I can't find any definitive information on the combustion chambers but either the pistons or the combustion chambers would have to be different on the LS2 cast 243 heads otherwise the compression would be 11:1 or more. And I do know these motors didn't have that much compression from the factory.....So where was the change made???? In the head or the piston??? I know on the 6.0 truck motors the change was made in the heads,,,to 71cc combustion chambers,,yet they also had the same port dimensions and D-shape exhaust port as the LS6's.

    Like I said, I wish I had a set of these later model 243's in my hand, I would love to poor the chambers and see where they are.

    As far as the castings and the triangular marks, that goes for all heads, I have a set of 241's like that as well.

    ahhh..well my money is on the pistons

  4. #44
    Member midi_2001's Avatar
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    I'm looking at head gaskets and standard (stock) thickness is .051".

    I found these http://www.trickflow.com/partdetail....&autoview= sku they're .045" thick compressed instead of .051". They'll bump the compression up a bit and I wouldn't think there would be any issues going only .006" thiner (e.g. intake fit, etc).

    $72 each at Summit. If I want to go cheaper ($$$ wise) everything is .051" thick and up. I wonder how much of a difference in compression .006" will make? Might not be worth the extra cash.

    Anybody, anybody, anybody?

  5. #45
    Moderator Firebirdjones's Avatar
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    Well it wouldn't make a ton of difference in compression but there are other advantages that are worthwhile.
    What it does do is increases the "quench" area or I should say makes the quench tighter. That's the flat area of the head that is inside the bore and covers about half the piston top.

    A tight quench is good for promoting swirl in the chamber which is a good thing. This helps prevent detonation (even at a slight increase in compression) and although it hasn't been shown to provide a power increase, it does promote and more complete burn and most engine builders strive for a tighter quench area.

    It's actually been shown that running a thicker head gasket and dropping the compression can actually cause a detonation problem because the quench area has been increased to a point of diminishing returns.

  6. #46
    Member midi_2001's Avatar
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    Quote Originally Posted by Firebirdjones View Post
    Well it wouldn't make a ton of difference in compression but there are other advantages that are worthwhile.
    What it does do is increases the "quench" area or I should say makes the quench tighter. That's the flat area of the head that is inside the bore and covers about half the piston top.

    A tight quench is good for promoting swirl in the chamber which is a good thing. This helps prevent detonation (even at a slight increase in compression) and although it hasn't been shown to provide a power increase, it does promote and more complete burn and most engine builders strive for a tighter quench area.

    It's actually been shown that running a thicker head gasket and dropping the compression can actually cause a detonation problem because the quench area has been increased to a point of diminishing returns.
    I was doing some research yesterday and your input makes a lot of sense. Thanks!!!!

  7. #47
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    I've got the same combo but having a little trouble picking the correct head gaskets any one know what the head bore on the gaskets should be 4.8 ls1 with 6.0 heads
    Last edited by sicmoto; 10-15-2014 at 10:17 PM.

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