Gen iv vs gen iii

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Dec 14, 2010 | 12:22 AM

mfernandez72490

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Gen iv vs gen iii

I wanted to know if the Gen IV heads were interchangeable with GENII?

Dec 14, 2010 | 07:41 AM

litle88

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Gen3 heads fit on gen4 but chances are your compression is going to be higher. Gen 4 heads will NOT fit Gen 3 because you'll need a 4.0 bore.
Google is your friend Amigo.

Dec 14, 2010 | 08:12 AM

KCS

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Quote:

Originally Posted by litle88

Gen3 heads fit on gen4 but chances are your compression is going to be higher. Gen 4 heads will NOT fit Gen 3 because you'll need a 4.0 bore.
Google is your friend Amigo.

That's not completely true. Not all Gen IV engines have LS3/LS7 heads. The GEN IV 6.0L and the 5.3/4.8L engines use cathedral port heads and can be used on the LS1/LS6/etc. GEN III shortblocks.

Dec 14, 2010 | 08:39 AM

redbird555

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also lq4 and lq9 are gen III engines can use gen IV heads because the bore is 4.0"

Dec 14, 2010 | 10:43 AM

litle88

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Quote:

Originally Posted by KCS

That's not completely true. Not all Gen IV engines have LS3/LS7 heads. The GEN IV 6.0L and the 5.3/4.8L engines use cathedral port heads and can be used on the LS1/LS6/etc. GEN III shortblocks.

Aren't cathedral heads gen3? Like I said gen 3 heads will work on gen 4 motors.
6.0 lq9/4 iron blocks gen3 are a 4.0 bore and yes I left that out sorry they can use gen4 heads.

Dec 14, 2010 | 12:00 PM

KCS

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Quote:

Originally Posted by litle88

Aren't cathedral heads gen3?

Not really. Gen IV is typically '05 and up where the reluctor wheel, cam sensor, etc changed. LS2's are considered Gen IV engines, and they utilize cathedral port heads.

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