Closed chamber bbc head?
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Closed chamber bbc head?

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    Senior Member H20MOFO's Avatar
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    Default Closed chamber bbc head?

    I dont ever hear of alot of peeps running these...like the 290's....and 063's. My compression is way low....have always wondered what taking away 18 cc's out of the combustion chamber...would do for me. Am I an idiot to think these heads may be an improvement over the alum. brodix bb2+ heads I have now. My 557 is only 8.4 to 1.....was orig. assembled for some boost.(cept the cam grind...knew I couldnt do it all at once). Right now I pull my AA cut to 4900-5kish would like to see 5k plus. More than anything...was curious why these are never used. I hear how the closed chamber ford heads can support a higher compression ratio/more ping resistant than an open chamber chev head.
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  3. #2
    gn7
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    Never compare, or even discuss Ford closed chamber heads in the same sentence with BBC closed chamber heads. Like saying cats and dogs are the same because they both have 4 legs. There is a huge difference between the two.

    The BBC closed chamber is a bath tub and almost as deep. The valves are very very shrouded, and basically POS.
    The BBC closed chambeR breaths so badly that even with the loss of compression, the open will almost always make more power IF CAMMED CORRECTLY!!!! simply due to breathing.

    You'll notice the Ford "closed chambe rlooks more like the BBC open head than the BBC closed head. It breaths much better also.

    Chevy closed chamber:




    Ford closed chamber:
    Last edited by gn7; 12-03-2011 at 09:50 PM.
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    Gone
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    Default So easy

    "Am I an idiot to think these heads may be an improvement over the alum. brodix bb2+ heads I have now."

    Yes.

    But the closed chambers make much better door stops.

    Next....

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    Good Job on the photo;s GN. Question, are they better than stock large oval port, peanut port? Where would they fit in? Valve sizes are stock.

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    Senior Member TNYoungblood's Avatar
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    I got a question for ya GN

    On the 468 I have got it's got Closed Chambered 291s and it's 13:1 compression. I won't to find a set of lumi heads to put on it. If I do this will I have to do a piston swap also? This engine is goin in the Cheyenne for racing

    Thanks



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    Senior Member H20MOFO's Avatar
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    Thanks fellas...its a question I have wanted to ask for a while. I guess that kind of explains why I've never seen an aftermarket bbc closed chamber head. The edelbrock claims to be a semi-open at 110cc's....thats the smallest chamber I can find. Guess there is no short cut for some squeeze or a new set of pistons.lol Thanks for the pics and explanation GN7
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    Senior Member Uncle Dave's Avatar
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    Thanks GN. That was a very helpful post.

    Uncle Dave

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    Senior Member vmaxed's Avatar
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    Default Heads

    Quote Originally Posted by TNYoungblood View Post
    I got a question for ya GN

    On the 468 I have got it's got Closed Chambered 291s and it's 13:1 compression. I won't to find a set of lumi heads to put on it. If I do this will I have to do a piston swap also? This engine is goin in the Cheyenne for racing

    Thanks
    Mike I got a set of BB PLUS 115cc and a set of Chevrolet 990 119cc.
    "DON'T JUST TELL ME IT WON'T WORK TELL ME WHAT WILL"

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    Senior Member Hass828's Avatar
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    Quote Originally Posted by H20MOFO View Post
    Thanks fellas...its a question I have wanted to ask for a while. I guess that kind of explains why I've never seen an aftermarket bbc closed chamber head. The edelbrock claims to be a semi-open at 110cc's....thats the smallest chamber I can find. Guess there is no short cut for some squeeze or a new set of pistons.lol Thanks for the pics and explanation GN7
    Sure there is! Put a large shot of NOS on that thing and it will haul. With the low comp. it will have a little wider tuning window .
    Racing is who gets there first, not who gets there on schedule.


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    cfm
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    Quote Originally Posted by H20MOFO View Post
    Thanks fellas...its a question I have wanted to ask for a while. I guess that kind of explains why I've never seen an aftermarket bbc closed chamber head. The edelbrock claims to be a semi-open at 110cc's....thats the smallest chamber I can find.
    Edelbrock has a 100cc chamber 290cc roval port head marketed towards the low compression flat top + dished cast piston 454's.

    Edelbrock.com - Cylinder Heads - Chevy - Big Block - Performer High Compression 454-O

  12. #11
    cfm
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    Quote Originally Posted by TNYoungblood View Post
    I got a question for ya GN

    On the 468 I have got it's got Closed Chambered 291s and it's 13:1 compression. I wan't to find a set of lumi heads to put on it. If I do this will I have to do a piston swap also? This engine is goin in the Cheyenne for racing

    Thanks
    Ck with your piston manufacturer and tell'm about the head your getting. Many times a closed chamber domed piston will fit fine with an open chamber head, but almost never the other way around.

    Many companies can/will mill their heads to say 112cc or (I remember Canfield used to go down to 110cc) so to get a little compression back for you.

  13. #12
    Foxwell Motorsports
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    Quote Originally Posted by TNYoungblood View Post
    I got a question for ya GN

    On the 468 I have got it's got Closed Chambered 291s and it's 13:1 compression. I won't to find a set of lumi heads to put on it. If I do this will I have to do a piston swap also? This engine is goin in the Cheyenne for racing

    Thanks
    You can get a set of AFR's down to 102cc. Put a set of 305's on that thing with small chambers and have Chris do a cam. With the TR she'll make some power.
    FOXWELL MOTORSPORTS
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  14. #13
    Foxwell Motorsports
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    Quote Originally Posted by H20MOFO View Post
    Thanks fellas...its a question I have wanted to ask for a while. I guess that kind of explains why I've never seen an aftermarket bbc closed chamber head. The edelbrock claims to be a semi-open at 110cc's....thats the smallest chamber I can find. Guess there is no short cut for some squeeze or a new set of pistons.lol Thanks for the pics and explanation GN7
    That really is the "right" answer.
    FOXWELL MOTORSPORTS
    STRAUB TECHNOLOGIES
    Performance Cylinder Head Specialties
    Custom Cams
    Complete Engines
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  15. #14
    Senior Member tigertooth's Avatar
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    Quote Originally Posted by steelcomp View Post
    You can get a set of AFR's down to 102cc. Put a set of 305's on that thing with small chambers and have Chris do a cam. With the TR she'll make some power.
    x2

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