I was told by someone from GM these were 317 heads. There are no numbers on them in the place I would expect to see them - like on my 243's. Someone went through the effort to CNC port these and it was done by a pro shop in Detroit. I am using them on a PD Blower LS6 project because I was told 317's were better for Boosted engines and I agree -- IF they really ARE 317's. On one end of there is a stamping that says "Pat Pen". I wouldn't think GM would put that on an OEM part - would they?
Here are some pics. Can anyone help me ID them? They ARE really nice - I just don't know for sure what they are.
Please help me solve this mystery...
Thanks


Would GM put this here??

Cathedral Intake

D-Shaped Ex Port

I would expect to see 317 on this flat

I would expect to see 317 on this flat too


Only a few Casting marks

The only Casting ID's

 

Chinese knockoffs?
CC a chamber and an intake port. At least then you'll know WHICH knockoff you have....

 

I think those are some aftermarket replacement casting.

 

The head has Castech's logo on it.
Castech heads (706) tend to crack more often.






OP's head with Castech logo



Example of Castech logo and frequent problem areas.


BTW - I dont think they are Chinese copies, the Chinese have too much pride and quality to slap Castech's logo on their copies. They'd copy a logo from one of the better casting companies.

 

Castech 706

Note the "battery" casting mark in the 5th pic

Not sure who would have stamped what might mean "patent pending" on such a thing

 

Looks like 99 beat me to it by a few seconds

 

They look like a 799/243 casting based on the combustion chamber shape. It looks like they ground down the internal part number as well that would have been in the rocker valley area.

The PAT PEN is not a factory marking.

I dont believe the 706/ 862 heads would have a 6.0 on the onder side like that. they usuall have 5.3

I can tell you they were cast in 2002...

 

https://www.motortrend.com/how-to/su...nder-head-test
Here is the image of each combustion chamber from that article. I would have to look at the junk 706 head I cut up. I am not sure if there is enough meat in the 706 casting to reshape the combustion chamber that much to resemble the 799/243 heads. the high point on the exhaust side of this casting is what concerns me.

 

Wow! Thanks for the quick replies!!
I'm leaning toward FastBrick's answer - because of the Chamber shape. (Nice pics too - I'll be saving them!) Much too flat on the Ex side for a 317 / 035. Here's another pic sitting next to a 241. It appears that the CNC guy ( A shop in Lansing) 'erased' some of the GM markings. Note the black circles. He must have had some special VooDoo - or thought he did - to stamp 'Pat Pen' on the ends. An ego thing, I guess?
Soooo, Scooby Doo says these were 799's that got the special treatment. The only difference between 243 and 799's were the Ex Valves - or so I'm told. I'm going boosted so these will give me little more CR and I'm OK with that.
BlackBird - Nice Pic as well! If the Castechs are problem prone - and the Port Guy KNEW that - I would think he would have erased that first. Jus Say'n.



Here's the back story...
My Son is a GM engineer. He got these heads from another GM guy in a 'package deal' - all Hot Rodders. Was told by the seller they were ported 243's (which, I guess they are if they are 799's). He did some research and asked another GM guy that knows A LOT about Heads & Gaskets. That guy told him they were 035 / 317 and had compelling reasons to back up his detective work. (I can post his comments in another thread if anyone is interested). I was gonna swap him my 243's for these once I got em off my C5 Z.
Here's another pic sitting next to my 243 - the chamber shape is pretty close to identical.



But why does my mystery head have 6.0 cast in it and the 243 say 5.7? Were 799's used on 6.0's? I plan on using a LS9 MLS Gasket but do I really need to if they really ARE 799's?? The saga continues.
Thanks again for all your talent!! Gotta LOVE smart guys, willing to help and a great forum.

 

The 243 also had a Castech head. But ony the 706 castings were prone to cracking.

The 243/799 were also used on the LS2 6.0L

 

It is possible they could have had the cumbustion chambers welded up and re shaped. Not many people do that though. If they were a 035/317 head that would explain it..

The only 243 heads that had different valves were the 02-04 Z06 heads. Those heads appear to have aftermarket valves any way.

 

Thanks for taking the time to educate me. I had a local shop go over them and put my BTR springs & seals in them. One valve was bent and got replaced - maybe that's why one is shiny. I agree that it is unlikely the chambers were welded - these were not expensive and that process would be.
So, I'm OK with the LS9 6.0 Gasket?
I'm adding a LSA Blower to a '03 Z06. Car was bone stock - not any more though. Doing LOTS to the engine and Rear End to strengthen it all. Hoping for 600+ WHP when done & tuned. A long way to go yet but having fun in the LS world. My GM Son & I did a LS1 swap in a '93 RX7. Was my first taste of the LS - I like it! He wants my 243's for that car - we traded what was supposed to be 317 / 035's. Now all THIS showed up. I just had a feeling they weren't 317's. Thanks again for the info - super helpful pics. Nice seeing it 'Black & White.'

 

243 and 799 heads used the same valves, as has been pointed out often in these forums. The ONLY real difference is the casting method. 243 is investment (I THINK...) and 799 is sand cast. Otherwise, identical.

 

I had read that as well. Do they look like 799 / 243 to you too?
Thanks again, guys, for all the help here!

 

They have that look like they have been bead blasted,, there was a outfit a long time back that would do a extrude hone-ish process to get rid of flash and casting marks, clean up the rough areas in the ports etc, "cnc bead blasting" , it was supposed to be a fast/cheap/easy way to get some power. Never saw them in person, the company didn't last long...

 

Ive seen that " battery" mark on 243s before.

 

My local guy blasted them just to clean them. It does appear that he got into the ports though. they had a machined surface when I got them - now it is dull. I'll ask. I recall the process you're referring to. Ran a slurry of abrasive thru ports to smooth & enlarge them. I thought it was a good idea.
Thanks again for all the help - you all get Scooby Snacks!

 

JumboShrimp, that's a fair point since the other markings were removed, why not remove the manufacturer's logo as well.

Does looking at these pics help us draw any conclusions?

OP's mystery head's chamber. Rotated image slightly.



My LS6/243's with tweaked chamber.

 

Likely 243 heads. Until you said that they had been blasted, I was going to say that they were Chinese castings of a CNC ported head after seeing the chambers (these exist).
Are you sure these were fully CNC ported? I can still see the casting marks on the inside of the intake ports.

 

When my son originally got these in a 'deal' he was told they were CNC'd LS6 heads. Because there were no markings - other than from the CNC work - he did some research. Was told buy an un-named GM source (with a serious power train title) that they were 035's (317's). The guy he got them from WAS gonna use them for a Boosted engine so we were all comfortable that they were 317's. Then I looked at the shape of the Chamber and started questioning it. I don't know the shop in Lansing that did the work but they WERE worked over and shaved .002 - That's from the guy my Son got them from and he is trustworthy. (AwesomeAuto - I'll take a closer look at the intake runners)
Why the hell he would 'erase' the GM logo and numbers, leave the Castech logo & then stamp 'Pat Pen' on em will always be a mystery. I'm now confident that the ARE 243 - 799's and will proceed with my project. I Just hope I don't have too much CR / Boost for a stock Bottom End. Guess we'll find out...
You people are a FANTASTIC bunch - thanks for all the effort!!