Head cc questions
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TECH Resident
Joined: Aug 2003
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From: orlando, florida
Head cc questions How much will the lq9 heads drop my compression? According to the write up in the internal engine section 72cc would equate to about 9.1:1 comp is this accurate? Because everyone i Talk to says it`s actually about 9.5:1 When said and done. Just wondering if i should put some cometic gaskets in there just to be safe? 
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Joined: Dec 2001
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From: Columbia, MD
Originally Posted by MYTURBOT/A
How much will the lq9 heads drop my compression? According to the write up in the internal engine section 72cc would equate to about 9.1:1 comp is this accurate? Because everyone i Talk to says it`s actually about 9.5:1 When said and done. Just wondering if i should put some cometic gaskets in there just to be safe?
72cc should be just a hair over 9.5:1
I use Cometic head gaskets. They supposedly are less prone to "blow out" under high boost.
dont have the number with me but you can order them directly from cometic
i got the .067" mls 4.0" bore to match the heads, if you use the 3.9's it will hang over and eventaully leak, been there done that.''
any ways my 6.0 heads actually cc'ed at 69ccs and i had them increased to 70cc's
which would drop the CR to 9.6-9.7 with stock gasket, but i also did a piston change head gasets at .067 which droped it to 8.9:1
i got the .067" mls 4.0" bore to match the heads, if you use the 3.9's it will hang over and eventaully leak, been there done that.''
any ways my 6.0 heads actually cc'ed at 69ccs and i had them increased to 70cc's
which would drop the CR to 9.6-9.7 with stock gasket, but i also did a piston change head gasets at .067 which droped it to 8.9:1
