Head CC Performance Question
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St. Jude Donor '11, '17
Head CC Performance Question
Assuming all else is equal, including final static compression.
Is there any appreciable difference between an engine with 76cc heads & the same heads with 64cc.
The 76cc would use flat top pistons & the 64cc would need dished pistons to achieve a static CR of 10.0.
Is there any appreciable difference between an engine with 76cc heads & the same heads with 64cc.
The 76cc would use flat top pistons & the 64cc would need dished pistons to achieve a static CR of 10.0.
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From: Who says "Nothing is impossible" ? I've been doing nothing for years.
You answered your own question there, and you didn't even know it 
Flat top pistons are more desirable to use in a high performance application because of the better flame travel over the top of the piston
Flat top pistons are more desirable to use in a high performance application because of the better flame travel over the top of the piston
Thread Starter
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From: South of giving a damn
St. Jude Donor '11, '17
Originally Posted by MotorHead
What you really want though is a flat top and 64cc heads
That's what I have in my 406ci, with about 11:1 CR
That's what I have in my 406ci, with about 11:1 CR
MotorHead, how do you keep detonation under control? I thought anything over about 10.5, even w/alum heads, was asking for trouble. I don't mind going this high, but 93 is as good as it gets around here. No Unocal or Sunoco 97 to be had.
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From: Who says "Nothing is impossible" ? I've been doing nothing for years.
One trick is no vacuum advance, that can put you over 50 degrees at times, and another is a big cam to bleed off cylinder pressure, having said that my cranking pressure is ~230PSI, so I am not sure how much the cam is bleeding off
I thought the general consensus around here was you could run 11:1CR with aluminum heads, I have run 91 octane with no problems, it likes 93-94 better though
I thought the general consensus around here was you could run 11:1CR with aluminum heads, I have run 91 octane with no problems, it likes 93-94 better though
