I can't seem to find any info about the 706 heads with this logo:



I know it's not the castech logo.... But who's is it?
Are these 706 heads good unlike the castech ones? Heads were on an 04 5.3 out of a Silverado.
Not looking for performance just reliability. Doing an engine swap on a k5 blazer and don't want to chance running the castech heads that are on my 5.3

 

Aren't those just factory heads? Are they ported or something?

 

Looks like a stock 706 head to me. I've not paid any attention to logos in stock heads but with single beehives and if the truck didn't have anything else aftermarket on it I'd imagine the heads were what gm put on it.

 

Look pretty factory.

 

That's what I was thinking. A company that's going to "mark" a head isn't going to do it there. That's a factory casting mark from GM.

 

Yes these are just factory heads, but so were the 706 heads made by Castech (battery looking logo) that had cracking issues. The heads I currently have are the castech ones and I'd rather swap them out before my swap so that I don't have a chance of them cracking from poor manufacturing.

 

You say in your original post that they "are not the Castech heads". If you're looking to remove them and replace them with other factory castings, then go ahead and do so. Heads like that can be had for less than $100.

 

Yes I don't believe the first photo is a castech head. I do not know who makes it however and if they are junk as well like the castechs, or if they are good quality. That's what I'm trying to figure out.

 

https://ls1tech.com/forums/generatio...706-heads.html

 

Thanks but how does this link help for what I'm asking? It doesn't

 

What makes you think the head is going to crack? Are you planning on throwing 25+ PSI of boost at it? If it's just a simple heads/cam/intake setup, or even a lower boost application, I wouldn't worry about it. Something else will fail before the head cracks. Just my opinion though.

 

I'm thinking they have a chance of cracking because it was a known issue for Castech 706 heads from 01-06. GM has a service bulletin about it and there's a lot of info about it online, including on this site. Just can't find any info on the logo pictured for what I believe is a non-castech head.

Why take the risk and run the 706 heads that can potentially crack? That's why I want to swap the heads.

 

This should help you out.

http://ww2.justanswer.com/uploads/Bl...t_loss_5.3.pdf

 

That's the info I know already about the castech heads. I keep trying to post a picture with the castech logo but the mods of this site aren't approving it or something.

 

Seems pretty simple to me. In the link I posted, it shows a picture that's stamped on the heads. Either yours has it, or it doesn't. If there is the marking where the bulletin indicates it's at, then they are the Castech heads. If no mark is there, you're good.

 

Yes I understand that already. Just want to know if anyone has any info on the head with the other cast marking.

 

Ppl beat the hell out of these things never really seen the heads cracking. Personally I wouldn't worry about it.

 

That's true and kinda what I was thinking when I first got this engine. But then I read a lot of stories about people having issues in their daily drivers, let alone beating the hell out of it.

 

I seen these heads melted from rough tunes from nitrous and boosted guys. Countless lbs of boost etc. if you feel uncomfortable about them pick another stock casting, all of which are pretty cheap.

 

Yep that's what I'm doing, picking another head because I found a deal on the heads pictured. 706 & 862 are the only options without machining as far as I can tell so I was trying to get more info on these particular 706 heads. If anyone has that info i'd appreciate it.