Mismatched heads???

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Jan 9, 2009 | 11:43 AM

shaguar_red

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Mismatched heads???

My buddy and I pulled apart the engine from his 1995 Formula and found the heads had two different casting numbers. One is 10128374 and the other is 10207643. We are going to have them resurfaced and mildly ported, but could this have caused problems with his formulas performance? And is it ok to go ahead and use the mismatched heads as long as we get them machined and port matched? Thanks guys.

Jan 9, 2009 | 05:33 PM

fuel

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From: seminole,fl

my porter told me my heads had diffrent casting #s. but still mad 420 to the ground

Jan 14, 2009 | 09:01 AM

shaguar_red

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hmm. anyone else had this experience?

Jan 14, 2009 | 09:29 AM

ss.slp.ls1

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From: Orange County, CA

Quote:

Originally Posted by shaguar_red

hmm. anyone else had this experience?

They are both LT1 alum heads and should be pretty much identical. Once ported, any casting differences, if any, will probably be non-existent.

Jan 14, 2009 | 10:16 AM

SpeedDensityZ

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From: Macclenny FL

Quote:

Originally Posted by ss.slp.ls1

They are both LT1 alum heads and should be pretty much identical. Once ported, any casting differences, if any, will probably be non-existent.

Agreed!! And it helps that they are both the casting numbers porters want to use. So, there is plenty of material to be removed.

Jan 16, 2009 | 11:55 AM

94Z28rag

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From: West Chester, PA

Quote:

Originally Posted by ss.slp.ls1

They are both LT1 alum heads and should be pretty much identical. Once ported, any casting differences, if any, will probably be non-existent.

Not true at all: http://www.camaroz28.com/forums/showthread.php?t=427346

374 and 643 are the "good" casting numbers, whereas the later years, 96-97 got lighter, slightly different heads from the factory and these are much less ideal for porting.

OP, both of your heads are good!

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