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Generation III Internal Engine
LM7 Exhaust port

Generation III Internal Engine 1997-2006 LS1 | LS6

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LM7 Exhaust port

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Sep 18, 2017 | 08:48 PM

#1

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From: Warren, Mi

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LM7 Exhaust port

Has anyone worked the bump at the base of the valve stem boss in the roof of the LM7 exhaust port and had any problems with the water jacket area? Does smoothing the bump cause a hot spot or breakout into the water jacket? I'd like better flow without causing a hydrolock issue. The wall thickness under the bump is supposed to be about 4-1/2 mm's. I'm thinking I removed about half of that material. Any information about past experiences would be appreciated. Thanks.

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Sep 18, 2017 | 11:07 PM

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From: JunkYard

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The one on the left is a 243.

The one on the right is a 241 head which would be similar to the 706/862 heads.

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Sep 18, 2017 | 11:12 PM

#3

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From: Central Cal.

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Looks like the port wall thickness is consistent enough that any bump can be ground off with no ill effects to the head.

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Sep 19, 2017 | 12:24 AM

#4

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From: columbus,ohio

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You can knock it down on each side of the boss , but it being down stream of the boss not much is gained flow wise, I would leave it.

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