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  1. #1
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    now-atomic orange
    2002 SLP M6 SS

    Diff in 862 vs 241 heads?

    Looking at both of these. I'm hearing the 241 is good-where does the 862 come in at?

    The 241 is cnc'd the 862 is stock (would need port work)

    $400 vs $550 for the 241 set.

  2. #2
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    now-atomic orange
    2002 SLP M6 SS

    Well, I guess like it or not I picked up the pch 241 cnc'd heads for 5 bills. They say the flow @ .600 is 290/220 which does appear to be better then stock, but not super outstanding. What gains should I expect from these heads with the LT's & upgraded exhaust & tune? What is the cc size on these?

    I'm considering just picking up a set of aftermarket rockers with an upgraded ratio vs a cam swap right now. What brand/gains should I see?

    If going with a cam, I guess I'd not do the rocker swap, but what cam would be a good choice for civilized street manners, stock style idle and yet decent enough gains to justify the expense? (at least 50hp).

    What else should I be doing while swapping over the heads? (hardened pushrods-titanium retainers-arp bolts-ect...?)
    Last edited by dbs1; 01-25-2010 at 10:47 AM.

  3. #3
    Veteran Hi-Po's Avatar
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    1999 TA WS.6

    862 is a 5.3 liter head. Smaller combustion chamber(61.5CC), increased CR.

    241 is a 5.7 liter head. Larger combustion chamber.

    Gains from a higher ration rocker arm (1.8 vs 1.7) are going to be minimal. Expect approximately 10 peak HP. IMO, if you have any plans of adding a aftermarket camshaft later down the road, pass on the 1.8 ratio rockers. It will limit what you will run, and you will end up swapping them out for stock 1.7's.

    The CC on those heads SHOULD be 66CC. That's if they have not been milled.

    For a camshaft recommendation, a good starter would be clicking on the link in my signature. Camshaft Guide. Read through that, then at the bottom, there are multiple dyno graphs showing some gains. Think roughly, 228/228 on a 114 LSA. Thats without the 1.8 ration rocker arms, Forget those.

    If doing a cam swap, along with your head swap, there is a decent run down of parts needed/wanted in that thread also.
    370 CI - Twin 6766 Turbo - Jakes stage 5 4L80E - MWC 9" - Holley Dominator

    Build in progress...

  4. #4
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    now-atomic orange
    2002 SLP M6 SS

    Thx for the reply! The 241 heads have been milled .010

  5. #5
    Sold: LS1 '85 El Camino ls1camino's Avatar
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    2000 Grand Prix GTP
    2000 Trans Am WS6 M6

    I thought stock rockers are 1.6, not 1.7.

  6. #6
    Veteran Hi-Po's Avatar
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    Quote Originally Posted by ls1camino View Post
    I thought stock rockers are 1.6, not 1.7.
    No, 1.7

  7. #7
    TunedbyFrost.com Tuner Frost's Avatar
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    Definitely keep stock rockers. Also definitely swap the cam. I have had a solid dozen cars with ported heads that made little to nothing over stock. Ported heads shine above where the stock cam works. Get an LS6 intake if you don't have a 2001-2002 as well.

  8. #8
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    now-atomic orange
    2002 SLP M6 SS

    Have (had ) an 02. Another guy may be taking it (long story) but I'll ask anyway-

    Mill these 241 heads to get a 11:1 cr, and use a 224/228 112lsa cam, redo dyno tune. Car has LT's and upgraded exhaust. heads are claimed to flow 290/220 @ .600.

    What gains should be seen with this? Will it require a different length pushrod? Will all other stock valve train parts work? Other then a gasket and bolt kit, what other items will be needed? thx!

  9. #9
    TunedbyFrost.com Tuner Frost's Avatar
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    You have to measure for pushrod length.. no one can look at what you have posted and tell you the exact length that you need.

  10. #10
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    now-atomic orange
    2002 SLP M6 SS

    Yeah, I think I'll wait on boththe pushrods and gasket/bolt set till we can check everything ti make sure we have no clearence issues. Wil probably go with an arp set.

    Expected Gains????

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