2007 head issues #243 vs. #799
Thread Starter
Instructor
Joined: Aug 2007
Posts: 146
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From: Aliquippa Pa.
2007 head issues #243 vs. #799
I read a thread not long ago on C6 general about a difference in the heads on the born in Oct. 06 C6's that GM used, they used #799 heads as opposed to #243 heads. The person who wrote the thread said his numbers on the dyno where significantly off from other vettes tested. They said there was a difference in the heads. I have an 06 manf. date is 02/06 it has#243 heads on it. My Cuz has an 07 manf. date 09/06 it has the #799 heads. They said in the thread that the #799 heads where used on the 5.3 liter V-8 . I also have a 08 silverado with the 5.3 engine and the heads on it are marked #799. My question is can anyone tell me is there a difference in performance, Did he get an engine that don't have the higher performance heads on it. What is the story on this???
Safety Car
Joined: Aug 2006
Posts: 4,347
Likes: 25
From: Apache Junction AZ
I read a thread not long ago on C6 general about a difference in the heads on the born in Oct. 06 C6's that GM used, they used #799 heads as opposed to #243 heads. The person who wrote the thread said his numbers on the dyno where significantly off from other vettes tested. They said there was a difference in the heads. I have an 06 manf. date is 02/06 it has#243 heads on it. My Cuz has an 07 manf. date 09/06 it has the #799 heads. They said in the thread that the #799 heads where used on the 5.3 liter V-8 . I also have a 08 silverado with the 5.3 engine and the heads on it are marked #799. My question is can anyone tell me is there a difference in performance, Did he get an engine that don't have the higher performance heads on it. What is the story on this???
BJK
Le Mans Master
Joined: Jan 2003
Posts: 8,596
Likes: 19
From: Portland Oregon
I have used both versions, while the 243 seems to be a "cleaner" casting there has been no variance in power. I have installed literally dozens of these heads in the past three years as part of head and cam packages. I do personally prefer the 243 casting as it is a cleaner casting. From what I have seen the 799 seems to be cast by a different method, and its chambers has a different finish as compared to the more prefered 243 casting. The differences are basically asthetic and does not have any negative impacts on performance, at least not on my dyno 
Thread Starter
Instructor
Joined: Aug 2007
Posts: 146
Likes: 0
From: Aliquippa Pa.
I have used both versions, while the 243 seems to be a "cleaner" casting there has been no variance in power. I have installed literally dozens of these heads in the past three years as part of head and cam packages. I do personally prefer the 243 casting as it is a cleaner casting. From what I have seen the 799 seems to be cast by a different method, and its chambers has a different finish as compared to the more prefered 243 casting. The differences are basically asthetic and does not have any negative impacts on performance, at least not on my dyno
Race Director
Joined: Feb 2006
Posts: 11,733
Likes: 15
From: SC
What was really interesting is the whole debate began after a tuner was at a loss as to why that car was so down on power. He told the owner of the vette it was the 799 heads.....wrong parts used during assembly of that LS2 motor....
I got swept up in the BS and started a thread to try and get to the bottom of what was going on after I found 799 heads used on my car. In the end my LS2 dyno'd right where is should've been. Still a mystery why that particular C6 (that started it all) was so down on power though.
I got swept up in the BS and started a thread to try and get to the bottom of what was going on after I found 799 heads used on my car. In the end my LS2 dyno'd right where is should've been. Still a mystery why that particular C6 (that started it all) was so down on power though.
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