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Compression ratio?

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Old Aug 11, 2005 | 12:19 PM
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Default Compression ratio?

I would like to know what will my compression ratio be if I had some LS1 5.7 heads milled .20 installed on my car. I plan on using gm head gaskets. Is there a formula to figure this out. I don't remind there being one in the jrp's awesome writeup. Thanks, that was a great write up!
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Old Aug 11, 2005 | 12:23 PM
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10.74 SCR using graphite .054

Last edited by PREDATOR-Z; Aug 11, 2005 at 01:35 PM. Reason: Goofed on piston deck value
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Old Aug 11, 2005 | 12:30 PM
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Originally Posted by PREDATOR-Z
10.38 SCR using graphite .054
Thanks alot for the quick reply.
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Old Aug 11, 2005 | 01:37 PM
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From: BFE
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Actually it is ~ 10.74, sorry
i entered a positive value for piston to deck instead of a negative for out of hole.
My apologies.
I PM's you
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Old Aug 11, 2005 | 01:44 PM
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PM your self with this link so you have it when ever you need it.
http://www.corvettec5.com/CR%20Calculator.htm
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Old Aug 11, 2005 | 01:49 PM
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Originally Posted by conan
PM your self with this link so you have it when ever you need it.
http://www.corvettec5.com/CR%20Calculator.htm
That one won't work since you can't enter a negative value for piston out of hole.

This is a good one:

http://www.rbracing-rsr.com/compstaticcalc.html
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Old Aug 11, 2005 | 02:05 PM
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Yep the one many of us are now using is the one above and the one in my sig

BTW I got 10.76. If you want to do this yourself.
Go right down the list with these numbers.
3.898
3.622
.054
-.007
0
63.34 (66.67 is a stock head. To figure out the new cc of the head you must subtrack for the mill. A common number used is every .006 milled equals a minus 1 cc. You are milling .020 which would make a 3.33 difference.) (Now take 66.67-3.33 which equals 63.34 and that is the new cc of the heads.

Last edited by JZ'sTA; Aug 11, 2005 at 02:10 PM.
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Old Aug 11, 2005 | 02:12 PM
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Thanks for the link sorry mine didn't work.
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