Hello everyone,
I have a 2004 Tahoe that unfortunately has the castech head porous issue. I am able to aquire a set of 243 heads for free.
So.. I have done some research and it looks like I can run these heads and actually get some power gain and get rid of my coolant loss into the oil all in one. Win win!

So here's my question as I haven't found a clear answer.. I know the heads must be milled .030 to keep the factory compression ratio. But is that all that's needed? Will all the factory gaskets fit correctly?

The motor has almost 160k on it but has been maintained very well. If this is all possible, I plan to just mill the heads and drop them on and call it good. Any other info would be appreciated!

 

Yes, they'll be fine, but before you do, consider the 862s made more power with a cam. If this is a daily driver and no plans for forced induction, you may be better off selling those for $350 or so and buying a set of 862s for $150. Hell, get the 862s cut .030 and pick up some there...probably gonna get slammed for saying this..haha


Surprising HP Numbers From Our Stock LS Cylinder Head Test

 

I believe the heads on there are the 862 heads. Which is surprising because it was typically the 706 heads that had the porous issue.

It's a daily driven Tahoe just to get the family around. While I would like to get a little extra power out of it as its kinda lacking, it's not my main concern.

 

I don't want to speak indefinitely here...but I thought 706s were the only ones cast in Castech facilities?

 

Look at the 243's, they will have the castech logo too!

Don't get caught up in the hype... That Myth has already been busted as pointed out previously...

 

Yup the 243 also have the castech logo. But have never heard of one of those having the porous issue. It was certainly worse on the 706 heads. But I guess can happen on the 862 also obviously.

I'm stuck between wanting to swap the heads and just throwing some form of "quality" (blue devil) stop leak in there

 

Nope.

The Molding process was different for the 862 Vs. the 706 head.

The 706 actually has a more consistent casting

 

Well...I have been wrong before. Hm.


https://www.performancetrucks.net/fo...astech-539613/

 

Just consistently thin...? lol

 

No, The porosity is in the area where the mold is joined together during the casting process.