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To achieve 11:1:1 compression.....

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Old Oct 16, 2002 | 02:12 AM
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Default To achieve 11:1:1 compression.....

What thickness heads gasket will I need?My heads are milled .30thous and I was wanting some more compression.Also what is my compression now?I hear 10:5:1 and I hear 10:8:1 what is it really?Thanks everyone.

<small>[ October 16, 2002, 02:14 AM: Message edited by: Alonzo ]</small>
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Old Oct 16, 2002 | 07:03 AM
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Default Re: To achieve 11:1:1 compression.....

Assuming stock displacement( 3.9x3.622 ) with milled 5.7L heads and stock thickness for gasket( 0.054" ); 10.5:1 compression. Using a 0.035" thick gasket would put you right at 11.0:1 compression. Hope this helps <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" />
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Old Oct 16, 2002 | 11:18 PM
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Default Re: To achieve 11:1:1 compression.....

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by ls1290:
<strong>Assuming stock displacement( 3.9x3.622 ) with milled 5.7L heads and stock thickness for gasket( 0.054" ); 10.5:1 compression. Using a 0.035" thick gasket would put you right at 11.0:1 compression. Hope this helps <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" /> </strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">Thank you very much I needed that.
<img border="0" title="" alt="[Big Grin]" src="gr_grin.gif" />
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Old Oct 17, 2002 | 10:48 AM
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Default Re: To achieve 11:1:1 compression.....

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by ls1290:
<strong>Using a 0.035" thick gasket would put you right at 11.0:1 compression.</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">Where do you get different thickness gaskets?
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Old Oct 17, 2002 | 11:16 AM
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Default Re: To achieve 11:1:1 compression.....

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by 2001CamaroGuy:
<strong>Where do you get different thickness gaskets?</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">Fel-Pro or Cosmetic should have something.
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Old Oct 17, 2002 | 05:09 PM
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Default Re: To achieve 11:1:1 compression.....

ls1290....

You said a stock disp. LS1 with .030" off the heads will yeild a 10.5 to 1 CR

How about .035" mill off the 5.7 heads with the stock head gaskets?
10.6 ?

Thanks,
Ron

BTW... Do you see any problems with a .035" flat mill of the heads? There must come a point where you run into problems with the sealing/alignment between the head and intake manifold.

<small>[ October 17, 2002, 05:13 PM: Message edited by: Kimchee and Rice ]</small>
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Old Oct 17, 2002 | 07:46 PM
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Default Re: To achieve 11:1:1 compression.....

ttt
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Old Oct 17, 2002 | 07:50 PM
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Default Re: To achieve 11:1:1 compression.....

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by Kimchee and Rice:
<strong>[b]BTW... Do you see any problems with a .035" flat mill of the heads? There must come a point where you run into problems with the sealing/alignment between the head and intake manifold.</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">Ron, we have gone .050" off the heads a few times without any problems. .035" would be fine.
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Old Oct 17, 2002 | 07:57 PM
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Default Re: To achieve 11:1:1 compression.....

Jason... As usual, you be da man! <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" /> Thanks

BTW, ever get a micrometer on that 220 cam?
(base circle)

Ron,
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Old Oct 18, 2002 | 09:34 AM
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Default Re: To achieve 11:1:1 compression.....

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by Kimchee and Rice:
<strong>How about .035" mill off the 5.7 heads with the stock head gaskets?
10.6 ?
</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">Yep. Assuming milling 0.035 will drop the chambers to 63.8cc from 67.3 and gaskets are 0.052" <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" />
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Old Oct 18, 2002 | 03:55 PM
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Default Re: To achieve 11:1:1 compression.....

Thanks for the info...

So, I assume the stock graphite head gaskets (98 year model) are .052" thick when installed?
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Old Oct 18, 2002 | 07:01 PM
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Default Re: To achieve 11:1:1 compression.....

Wow 10.5:1 is news to me. I was told buy a couple different sponsors that I would be at 10.8:1 with .030" off my 5.7L heads.

I am using GM head gaskets. Maybe I will look into the thinner gaskets. I would like to be closer to 11:1.

Mike
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Old Oct 18, 2002 | 07:42 PM
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Default Re: To achieve 11:1:1 compression.....

I'm at 10.8:1 with 5.7L heads with .040 milled off.. You do have more in there if you go with thinner gaskets... <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" />
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Old Oct 18, 2002 | 09:19 PM
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Default Re: To achieve 11:1:1 compression.....

A buddy of mine is running LS1 5.7 heads milled to the point of trashing them, ~.064 or so and has no alignment problems with his LS6 intake.

Josh
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Old Oct 18, 2002 | 10:08 PM
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Default Re: To achieve 11:1:1 compression.....

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by Damian:
<strong>A buddy of mine is running LS1 5.7 heads milled to the point of trashing them, ~.064 or so and has no alignment problems with his LS6 intake.

Josh</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">WOW! That is alot.. <img border="0" title="" alt="[Eek!]" src="gr_eek2.gif" />
In every other engine I am familiar with, that much would make alignment problems to the point that the intake just would not bolt to the heads. With a long duration cam, I would think your freind would have very serious piston/valve clearance problems.

It really suprises me that the LS1 can get by with that much of a flat mill.... Wow! There can't be much meat left on those heed surfaces.
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Old Oct 20, 2002 | 01:46 PM
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Default Re: To achieve 11:1:1 compression.....

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by Kimchee and Rice:
<strong> </font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by Damian:
<strong>A buddy of mine is running LS1 5.7 heads milled to the point of trashing them, ~.064 or so and has no alignment problems with his LS6 intake.

Josh</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">WOW! That is alot.. <img border="0" title="" alt="[Eek!]" src="gr_eek2.gif" />
In every other engine I am familiar with, that much would make alignment problems to the point that the intake just would not bolt to the heads. With a long duration cam, I would think your freind would have very serious piston/valve clearance problems.

It really suprises me that the LS1 can get by with that much of a flat mill.... Wow! There can't be much meat left on those heed surfaces.</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">His setup is quite unique compaired to what most people are used to seeing on the board. He has valve reliefs cut in the pistons though, so no problems there. The intake bolts up fine....

Josh
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