I still have found NO info from GM myself on the 799 casting. Still looking...
Calling all LS2 Experts
Le Mans Master
Joined: Oct 2005
Posts: 5,038
Likes: 878
From: Tampa Florida
Here's an interesting case. I have a 10/30/2006 build date ...and one of each head. The passenger-side casting is a 243 and the driver's-side (viewable just underneath and behind the alternator) is a 799. Obviously, I'm hoping that the CNC-finished heads are determined to be the same part.
-Ernie
OH NO A HYBRED...
-Ernie
OH NO A HYBRED...
Melting Slicks
Joined: Nov 2003
Posts: 3,375
Likes: 1
From: Northern CA
Melting Slicks
Joined: Oct 2006
Posts: 2,905
Likes: 1
Safety Car
Joined: Dec 2004
Posts: 4,276
Likes: 8
From: Tucson AZ
St. Jude Donor '08-'09-'10-'11-'12-'13-'14-'15
Very interesting, earlier this week I dyno tuned a C6 with Kooks, and a Corsa cat back. I was expecting to see something in the neighborhood of high 360s to low 370s on my Mustang dyno. I have got as much as 375 with a header only C6 on many occasions but not on this particular car. This was an 05 C6 M6 car and no matter what I did I could not get there. Maybe this head issue could be a problem, I will certainly have my customer check his casting numbers.
By the way folks, I pulled a whopping 353!!! Anybody want to trade 243 heads for 799's...or 862's...or a combinatiion of any of the above!
Last edited by Kreuzen; Mar 22, 2007 at 05:44 PM.
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Melting Slicks
Joined: Jan 2002
Posts: 3,419
Likes: 0
From: Arlington TX
Not trying to stir anything but a few years ago i received a letter in the mail stating that a class action lawsuit was filed against Hyundai (sorry that was my wife's car) because they were advertising one horsepower number when their cars were in fact putting out less than what was advertised. If GM is advertising 400-405 hp with the LS2 castings but you're only getting 390 or whatever, maybe that would fall under this too...just a thought. Oh and i did get a check in the mail for the class action lawsuit. It was like a 5hp difference and i got like $200 or something... 
Melting Slicks
Joined: Jan 2002
Posts: 3,419
Likes: 0
From: Arlington TX
Ah here's a link to the lawsuit..found it..in case anyone wants to read it...
Hyundai Offers $85 Million to Settle Horsepower Suit
Hyundai Offers $85 Million to Settle Horsepower Suit
Thread Starter
Racer
Joined: Jan 2006
Posts: 409
Likes: 1
From: Charlotte NC
Thread Starter
Racer
Joined: Jan 2006
Posts: 409
Likes: 1
From: Charlotte NC
Melting Slicks
Joined: Oct 2006
Posts: 2,905
Likes: 1
Bob, I think your discovery of the 799 head has got a bunch of us scratching ours. The earlier post was correct, the 799 was the head for the early C5 Z06 rated at 385HP, but it may have been CNC'd to match the 423s. Like I've stated before, we need a GM rep, be it mechanic, service leader,etc to step forward and clear this up and a back to back dyno of the two different set ups would be nice too.
Pro
Joined: Aug 2006
Posts: 547
Likes: 0
From: Dayton Ohio
243 on my '05.
I suspect that this is much ado about nothing.
I can't post the link but this comes from one of those popular auction sites
"If you have been watching my listings over the past month you have noticed that I am quickly becoming "the" source for clean 6.0L parts such as heads blocks and cranks, please check my previous listings and keep track of what I have coming up soon. Coming in soon are more 6.0L parts as well as other Gen III engines. Let me know what your looking for.
You are bidding on a core set of GM Gen III aluminum heads. Casting number 799 (same as 243), small chamber, 1761 Miles. A105 and A125 casting, 2005 model, excellent condition! Please check with your dealer to be sure this is the exact one for your application. May fit other applications, my description is only a guide and I cannot guarantee it is 100% correct, just what I found. Sold as-is! "
I suspect that this is much ado about nothing.
I can't post the link but this comes from one of those popular auction sites
"If you have been watching my listings over the past month you have noticed that I am quickly becoming "the" source for clean 6.0L parts such as heads blocks and cranks, please check my previous listings and keep track of what I have coming up soon. Coming in soon are more 6.0L parts as well as other Gen III engines. Let me know what your looking for.
You are bidding on a core set of GM Gen III aluminum heads. Casting number 799 (same as 243), small chamber, 1761 Miles. A105 and A125 casting, 2005 model, excellent condition! Please check with your dealer to be sure this is the exact one for your application. May fit other applications, my description is only a guide and I cannot guarantee it is 100% correct, just what I found. Sold as-is! "
Thread Starter
Racer
Joined: Jan 2006
Posts: 409
Likes: 1
From: Charlotte NC
I sent Gunnar at Patriot an email: No response. I sent Bowling Green an email: No response.Where are all the experts? I'm getting opinions. No facts.
Sorry for the rant, but this is really frustrating.
Are the 799 heads ligitimate? Are they the same as 243's? Did GM slip up and put the wrong engine in my car? The questions continue to go unanswered.
Safety Car
Joined: Dec 1999
Posts: 4,148
Likes: 5
From: Roxbury NJ
It's pretty obvious at this point that a bunch of 07's got 799 heads. We've been working on and talking about these cars along with C5s for years, so we also know that they were never used on a C6 (or a Z06) before 07. The only question that remains is this: Do they flow the same at a 243? If they're putting them on an LS2, I bet they do. All the stats we've seen say that they have the 210cc port.
"CNC" isn't a factor here, GM doesn't CNC the ports on any of these heads. Also, when the Z06 jumped from 385 to 405 hp, it had nothing to do with the head ports.
"CNC" isn't a factor here, GM doesn't CNC the ports on any of these heads. Also, when the Z06 jumped from 385 to 405 hp, it had nothing to do with the head ports.
Last edited by Flareside; Mar 22, 2007 at 09:15 PM.