closed chamber VS. open chamber ???????
Thread Starter
Heel & Toe
Joined: Aug 2004
Posts: 18
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closed chamber VS. open chamber ???????
I'm putting the original BB back into my car. The heads that I have to put on it are 3964290s, they are closed chambered and dated K 15 9 and K 5 9. So, I assuming that they are 69 heads and not true to my car I can live with that. OK to the question ...... I hear talk about open chamber flowing better than closed chamber. Which is better and would these heads perform well in my car?
Race Director
Joined: Nov 2000
Posts: 11,872
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From: Waterloo ontario Canada
Originally Posted by GDaina
Open chamber, by far are better, cleaner burning.....
The block was kept consistant and only the heads were changed.
Burning Brakes
Joined: Mar 2004
Posts: 923
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From: Austin Tx
Stick with the closed chamber. If you had open chambered heads, you could get larger dome pistons to make up the lost compression. That would be the ideal scenario; better flow, lower emissions, high compression.
Race Director
Joined: Feb 1999
Posts: 16,978
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From: In Dreams There Is Truth Ohio
Originally Posted by norvalwilhelm
Open chamber lower a compression ratio and I have seen a magaizine test where 4 sets of heads were prepared and bolted on the test mule. The closed chamber rectangular port won the shootout over the other 3.
The block was kept consistant and only the heads were changed.
The block was kept consistant and only the heads were changed.
That test is not valid...assuming 11:0 closed chamber pistons were run, that means when the open chamber heads were used, the c.r. was 9:1. If you run identical C.R. with both sets of heads, the Open Chamber will win, hands down...it's in the spark travel...the open chamber heads...the spark is unshrouded....cleaner burning, less emmissions...more power.....
Race Director
Joined: Nov 2002
Posts: 12,142
Likes: 54
From: Taylor Michigan
Originally Posted by GDaina
Open chamber heads lose 2 points in c.r. vs. close chamber heads..
That test is not valid...assuming 11:0 closed chamber pistons were run, that means when the open chamber heads were used, the c.r. was 9:1. If you run identical C.R. with both sets of heads, the Open Chamber will win, hands down...it's in the spark travel...the open chamber heads...the spark is unshrouded....cleaner burning, less emmissions...more power.....
That test is not valid...assuming 11:0 closed chamber pistons were run, that means when the open chamber heads were used, the c.r. was 9:1. If you run identical C.R. with both sets of heads, the Open Chamber will win, hands down...it's in the spark travel...the open chamber heads...the spark is unshrouded....cleaner burning, less emmissions...more power.....
Melting Slicks
Joined: May 2001
Posts: 2,131
Likes: 4
From: May help you? You can sure as hell try!
Race Director
Joined: Nov 2002
Posts: 12,142
Likes: 54
From: Taylor Michigan
Originally Posted by LemansBlue68
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Melting Slicks
Joined: May 2001
Posts: 2,131
Likes: 4
From: May help you? You can sure as hell try!
Originally Posted by Ironcross
What should I be looking for, except that I dont use any of them. All mine are rectangular port heads in both my closed and open chamber engines.
