2004 5.3 engine ?'s
11-08-2012, 10:21 AM
#1
2004 5.3 engine ?'s Im looking at picking up this engine that is local to me and out of a wrecked 2004 silverado truck with 120k on it. I found out it has 799 heads on it and I thought these were only on the newer 5.3's, not the 2004's. Thoughts anyone, is it worth it or should I move on? What are some of the other specs on this engine like the "cross" stamped pistons, are they better or? Enlighten me please...
11-08-2012, 07:35 PM
#2
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I own an 04 silverado and have had a whipple supercharger on it for about 60000 miles now. Truck makes 617 hp at 16 -17 lbs on a bone stock motor, I have literally done nothing but add injectors, fuel pump and supercharger thats it. Im not 100% on heads but I think there 799's , would have to check again to make sure. Dont know more on the motor but figured Id at least put some numbers up here.
11-08-2012, 07:54 PM
#3
2004 is the year they transitioned to the Gen4 engines, which are more desirable. The problem is that some 2004 trucks have 2003 engines and some have 2004 engines. Mine was from an 04 Silverado but the engine was made in 03 according to the casting near the water pump. I haven't verified this, but was told the late model engines have 13mm valley cover bolts and the earlier ones had 10mm bolts. I think 799s only came on Gen4 engines too.
11-08-2012, 08:28 PM
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gen 4 engines didnt get into the trucks until 07 with the body style change. It could be a gen 4 from a 05 up trailblazer. Deff not a silverado. The 799 heads DID come on the L33 gen 3 5.3 from the 05 silverado/sierra. Is it possible its actually an 05 engine not a 04?
11-08-2012, 08:34 PM
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by chance is the engine an aluminum engine??? My brother has a 5.3 in his Envoy XL and i am pretty sure that it has 799 heads. His engine code IIRC is LM4. I am not familiar with that code although i have not done a search either.
11-08-2012, 08:39 PM
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The LM4 is an alluminum version of the LM7 found in the trucks. Its a gen 3 and im pretty sure they only were in the 04 TB/ envoy. Not sure i have ever seen one with 799 heads though. i think the L33 was the only gen 3 to get those.
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11-09-2012, 07:15 AM
#10
2004 is the year they transitioned to the Gen4 engines, which are more desirable. The problem is that some 2004 trucks have 2003 engines and some have 2004 engines. Mine was from an 04 Silverado but the engine was made in 03 according to the casting near the water pump. I haven't verified this, but was told the late model engines have 13mm valley cover bolts and the earlier ones had 10mm bolts. I think 799s only came on Gen4 engines too.
If its a factory truck motor, its probly a 2005 l33 engine, check block, if its aluminum your golden.
11-09-2012, 07:05 PM
#11
Thanks for all the replies guys. All I know is he read the numbers off the heads and confirmed they are 799's. He also said the truck was his brothers and it was an 04. He's not sure if block is aluminum or cast as he didnt see any rust near the head surface and didnt have a magnet close by, hmmm. I could tell he was a younger guy and wasnt sure. I guess $500 is a good price no matter if alum or iron as long as the 799's are there? Thanks again.
