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Hey guys, I just picked up my 05 5.3 engine from the salvage yard. I was putting it on the stand when I noticed the casting number on the head was 799. Do these sound familiar? The closest thing I can come up with it is a pre-production LS6 head. The engine is an L33 all aluminum high output.
Thanks,
John
Well, I researched the answer to my own question. I'll post here so if anyone else needs the info it'll be here to search for.
The 799 heads are in fact an LS6 casting. They list part no. 12564825 for the 01-04 LS6 engines and the L33. "The L33 takes its cylinder heads from the LS6. Originally developed for the Z06 Corvette, these heads improve airflow in and out of the engine. With their pent-roof combustions chambers and new flat top pistons (the pistons in other Gen III Vortec 5300s have a slight sump in the piston deck), the L33’s compression ratio increases from 9.5:1 to 9.9:1. This increase improves the engine’s volumetric efficiency yet still allows it to achieve full power with regular grade gasoline." They have a D shaped exhuast opening. The heads have a 65cc combustion chamber and a 210cc intake runner.
The L33 also has a higher lift factory camshaft checking in at 0.482" for both intake and exhaust with the 1.7 rocker. It is also interesting to note that the L33 has a polymer-coated piston to enable tighter bore clearances and reduce piston motion. This coating also reduces cold scuffing and engine noise.
Is that a trailblazer 5.3 or out of an SSR truck?
Awesome find.
The L33 is the HO 5.3 found in 05+ 4x4 1500s
John
Cool, an aluminum block in a 4x4 2005+.
I guess everyone that buys the L92 option gets the aluminum block 6.2.
<div class='quotetop'>QUOTE(RedHeartbeat @ Nov 27 2006, 09:31 PM) [snapback]74739[/snapback]</div>It is an option on the 4x4/Z71 models. It is not standard. My boss has a 05 Z71 extended cab with the L33 and my friend has a 05 crew cab with the standard 5.3. Its like a $800 option if I remember correctly.Quote:
Cool, an aluminum block in a 4x4 2005+.
I guess everyone that buys the L92 option gets the aluminum block 6.2.
[/b]
John