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sTOCK HEADS MILLED??COMPRESSION??

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Old 06-09-2005, 03:07 PM
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Default sTOCK HEADS MILLED??COMPRESSION??

If I had my stock heads milled 30 thousands, what would my compression be??
also if you put 3.905 forged pistons what is your dis with stock heads??
Old 06-09-2005, 04:28 PM
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every cc is around .1 point in compression

Last edited by rcfast; 06-10-2005 at 12:18 PM.
Old 06-09-2005, 09:52 PM
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Originally Posted by NickcZ28
If I had my stock heads milled 30 thousands, what would my compression be??
also if you put 3.905 forged pistons what is your dis with stock heads??

Actually, it depends on many factors such as cid, head cc's, etc.

Here is a calculator:

http://www.c5frc.com/calculators/Com...Calculator.htm

Just subtract 30 thousands from your gasket thickness to get an estimate...
Old 06-09-2005, 09:54 PM
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Did you intend to say ever .010 milled off gives .1 pt increase in compression?
Old 06-10-2005, 08:31 AM
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and does angle milling do a but number on the cc of the chambers??
Old 06-10-2005, 09:06 AM
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Every .006 mill is 1cc, so (LS1) 66.67cc - 5cc = 61.67cc head

With stock GM graphite gaskets you'll be at ~11.0:1 SCR
Old 06-10-2005, 10:25 AM
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The calculator differs... it calculates 10.7:1 for those numbers.
Old 06-10-2005, 10:45 AM
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Head CC volume vs Compression Ratio:
______________________________________________

The below CR numbers are with the stock GM 5.7L displacement LS1 graphite head gaskets installed.

Installing the thicker 2003 GM MLS head gaskets will decrease your compression ratio by approx 0.1 - 0.2

72.27cc = 9.1 CR
71.71cc = 9.2 CR
71.05cc = 9.3 CR
70.59cc = 9.4 CR
70.03cc = 9.5 CR
69.74cc = 9.6 CR
68.91cc = 9.7 CR
68.35cc = 9.8 CR
67.79cc = 9.9 CR
67.23cc = 10.0 CR
66.67cc = 10.1 CR (stock LS1 head spec)
66.11cc = 10.2 CR
65.55cc = 10.3 CR
64.99cc = 10.4 CR
64.43cc = 10.5 CR (stock LS6 head spec)
63.87cc = 10.6 CR
63.31cc = 10.7 CR
62.75cc = 10.8 CR
62.19cc = 10.9 CR
61.63cc = 11.0 CR (61.67cc would be a micron less)
61.07cc = 11.1 CR
60.51cc = 11.2 CR
59.95cc = 11.3 CR
59.39cc = 11.4 CR
58.83cc = 11.5 CR
58.27cc = 11.6 CR
Old 06-10-2005, 10:49 AM
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Originally Posted by PREDATOR-Z
Head CC volume vs Compression Ratio:
______________________________________________

The below CR numbers are with the stock GM 5.7L displacement LS1 graphite head gaskets installed.

Installing the thicker 2003 GM MLS head gaskets will decrease your compression ratio by approx 0.1 - 0.2

72.27cc = 9.1 CR
71.71cc = 9.2 CR
71.05cc = 9.3 CR
70.59cc = 9.4 CR
70.03cc = 9.5 CR
69.74cc = 9.6 CR
68.91cc = 9.7 CR
68.35cc = 9.8 CR
67.79cc = 9.9 CR
67.23cc = 10.0 CR
66.67cc = 10.1 CR (stock LS1 head spec)
66.11cc = 10.2 CR
65.55cc = 10.3 CR
64.99cc = 10.4 CR
64.43cc = 10.5 CR (stock LS6 head spec)
63.87cc = 10.6 CR
63.31cc = 10.7 CR
62.75cc = 10.8 CR
62.19cc = 10.9 CR
61.63cc = 11.0 CR (61.67cc would be a micron less)
61.07cc = 11.1 CR
60.51cc = 11.2 CR
59.95cc = 11.3 CR
59.39cc = 11.4 CR
58.83cc = 11.5 CR
58.27cc = 11.6 CR

Try using that calc that was posted. See if you can get the numbers to work out. I'm just trying to clear up if this calc should actually be used by anyone, and why the numbers differ.
Old 06-10-2005, 01:02 PM
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So if I milled 30 thousands off and have a 3.905 bore Im at 11.0 to 1?????
what cc are my heads now??
Old 06-10-2005, 01:13 PM
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Every .006 mill is 1cc, so (LS1) 66.67cc - 5cc = 61.67cc head
Old 06-10-2005, 01:14 PM
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Thanx alot man does this effect HP??




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