LS4, LS6 Heads

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Sep 14, 2006 | 09:33 AM

'VETTE PHASE

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Melting Slicks

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From: Powell TN

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LS4, LS6 Heads

I've read that the 5.3 LS4 has LS6 heads on it. Is this the exact same head or is there some minor changes (smaller valve size, non sodium filled, different ports, etc.)that would not make them worthwhile?

Sep 14, 2006 | 10:23 AM

dmiz0420

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From: Northern Virginia

smaller combustion chamber on the ls4, 59cc so higher compression, watch your piston to valve clearance with big cams

Sep 14, 2006 | 10:51 AM

greg_nate

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Quote:

Originally Posted by dmiz0420

smaller combustion chamber on the ls4, 59cc so higher compression, watch your piston to valve clearance with big cams

Yeah, but what about valves and springs?

Sep 14, 2006 | 12:19 PM

fdxpilot

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From: Ocean Springs MS

Quote:

Originally Posted by greg_nate

Yeah, but what about valves and springs?

The chambers and ports are smaller, as well as one of the valves, the intake, IIRC. They will require porting and new valves to flow better than LS1 heads. The only bonus is the smaller chambers. LQ9 (HP 6L truck heads) have the same ports as LS6s, with larger (72cc) chambers and non-sodium filled valves.

Sep 15, 2006 | 08:43 PM

'VETTE PHASE

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Melting Slicks

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From: Powell TN

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Quote:

Originally Posted by fdxpilot

LQ9 (HP 6L truck heads) have the same ports as LS6s, with larger (72cc) chambers and non-sodium filled valves.

Is this a Vortec head?

Sep 15, 2006 | 09:38 PM

fdxpilot

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From: Ocean Springs MS

Quote:

Originally Posted by 2000C-5

Is this a Vortec head?

They call it a Vortec in the trucks, but it is an LSx engine, the source of the 6L iron blocks many have used to make big cube strokers before the LS2 came along. As mentioned, the LQ9 head is the same casting as the LS6 with 72cc chambers.

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