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Anyone port the head chambers to drop compression.

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Old Sep 20, 2007 | 03:12 PM
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Default Anyone port the head chambers to drop compression.

Its a 370 with 12cc Mahles and 72cc 317's. With a GM MLS gasket, compression looks to be around 9.5 to 1. I was thinking of polishing or opening up the chambers a little to drop a couple points. Or should I just use a thicker gasket. recomendations???
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Old Sep 20, 2007 | 09:37 PM
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OK to do if you know where there is extra material to be safely removed. Risky if you don't, unless you are just polishing everywhere and only removing a total of ~2cc's of material.

I wouldn't go over a .041" gasket. Is your deck zeroed to your pistons or are you slightly 'in the hole' at TDC? If your deck is zeroed, you could get a .050" gasket in there.

What's the worry? Just intercool the hell out of it, and then add alky if you have problems.

Jim
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Old Sep 21, 2007 | 02:44 AM
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nothing wrong with boost on 9.5:1. you will just have to run race gas on high psi. as long as you have a good intercooler to keep the iats down. my 382 is at 9.8:1
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Old Sep 21, 2007 | 03:49 AM
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Originally Posted by blown90lx
nothing wrong with boost on 9.5:1. you will just have to run race gas on high psi. as long as you have a good intercooler to keep the iats down. my 382 is at 9.8:1

and how much boost can u run on pump fuel say 93 for eaxmple--
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Old Sep 21, 2007 | 08:06 AM
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Originally Posted by LS1NOVA
Its a 370 with 12cc Mahles and 72cc 317's. With a GM MLS gasket, compression looks to be around 9.5 to 1. I was thinking of polishing or opening up the chambers a little to drop a couple points. Or should I just use a thicker gasket. recomendations???
How did you come the conclusion that the compression level is 9.5:1? I get 9.2:1 with a 0.041" gasket and 9.0:1 with a 0.054 gasket with -12cc pistons and 72cc chambers.

Keith
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Old Sep 21, 2007 | 08:53 AM
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My machinist calculated it quick. The block and heads have both been decked .005.
The MLS gm gaskets are around .050 crushed right. If it is around 9.2 I wont worry but if it is 9.5 I will polish the chambers to maybe loose a couple points??
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Old Sep 21, 2007 | 06:31 PM
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how much boost you can run all depends on how cool you can keep the air charge.
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Old Sep 21, 2007 | 07:42 PM
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I caculated it online and found it to be 9.2. Ill just run it.
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