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Maximum milling on LM4/LM7 862 Heads

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Old 05-06-2013, 10:04 PM   #1
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Default Maximum milling on LM4/LM7 862 Heads

Hey guys,

I am looking at increasing my CR on my stock LM4 and was wondering what the max amount I can mill off of the 862 heads. I am hoping to get into the 11:1 range if possible. I also have a 224/224 .581/.581 114LSA cam and springs going in at the same time. Thanks!
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Old 05-07-2013, 11:11 AM   #2
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LM4 has flat top pistons I'm 95% sure

Just mill the head .03 and your at 11:1 compression with stock height .051 gaskets. I would not milled heads more than this! some people will mill a max of .04 on 243s

Your piston to valve clearance should be fine but I would defiantly do some research to make sure b/c of the flat tops.

You will need to order a push rod length checker if you mill the heads. All blocks can be different so don't listen to somebody that tells you the "proper length" check for your self.

Should be around a 7.375 but like I said check!
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Old 05-07-2013, 03:01 PM   #3
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Thanks Camin!

I think the LM4 still has the dished pistons though. The L33s came with the flats.
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Old 05-11-2013, 11:18 PM   #4
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.030 is most i would mill....
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