One or both surfaces is not flat then. Get a good straightedge on it next time its off, and I bet you will be shocked it held any cylinder pressure, let alone boosted cylinder pressure.
How much drive pressure is your turbo making? Thats just as bad if not worse than boost.

 

I had both surfaces machined ts machined on the 2nd gasket.. they have been just fine since then...i dont know how much drive pressure its making..

 

I haven't talked to Cometic lately, but last I heard they were having issues with them not sealing. So, back to square one.

Where are you blowing the gasket out at? Is there a pattern to the failures?

You had the block decked? Again, I want to know if you have a pattern to the failure points.

My first impression is something is either not flat or not clamping down correctly, because you should not have problems without boost, unless for some reason timing is so far advanced that you get serious cylinder pressures. Drive pressure shouldn't be much of an issue until the turbo is singing.

 

All but one have been right on the front of the motor.. timing should be fine with just an edge comp.. what is decking the block??

 

IN order to get the block surface flat, you have to deck it, which is done with the motor out of the truck in the machine shop. That was what I was asking. So, you probably didn't deck the block, you had the head resurfaced.

I think you need to take a good quality straight edge and a flashlight to your block. You can get a honing stone or lapping stone to clean the surface of the block.

 

Its not the block..
or the head..