So ive got a 2000 silverado with a 76mm turbo and it keeps blowing the head gaskets. The first time it did it was before I put on the turbo and I had the cnc port, polished and milled .030 while I had it apart. Then fast forward a few months I installed the turbo and took it to get tuned and it was running hot so I took it home and did some diagnostics and determined head gaskets again so that time I just rushed and slapped some gaskets in and that didn't work gaskets blew right away, 3rd time was about 3 weeks ago so I pulled the heads and sent them to the machine shop and they cut the .010 more so there now at .040 and I used btr gaskets and arp head studs and everything seems OK for about an hour then once again coolant spraying from fill spigot and exhaust has moisture and I notice coolant under the valley plate. HELP! IM AT A LOST, ive tried everything

 

Did you pressure test your cooling system to confirm it was the head gasket?

 

no, yesterday was the first start up and it was dark when I noticed it. It was running smooth and then all of a sudden started bubbling the water from the coolant fill spigot and then I checked the exhaust and it was misting just as it's done before when the gaskets blew. The only strange thing I notice this time that was different was the coolant under the valley plate.

 

Did you verify correct orientation of HG? Unfortunately there was a batch of mis-labeled HG from BTR (and a few others) that even though it says FRONT is not the case and blocks the front coolant passage. Go take a look where the HG tabs are sticking out on the bottom of the head, if they are not towards the front you might have your culprit.

No idea who this fella is but here you go for visual:

 

when I installed the head gaskets I don't pay attention to the front or back thing, I wish it was something that simple but I've installed enough head gaskets on this thing that I know to make sure the coolant ports are lined up on gaskets and block. But my tabs are towards the front, I'm leaning towards something either being wrong with the block or maybe for some reason it's not sealing well enough. I torqued it to 80 pounds. The coolant is actually coming from under the valley plate on the front by the water pump

 

Pressure test the cooling system. Then report back.

 

will do
held the 15 pounds all night

 

Holding 15 pounds, has been for about 1 hour

 

What’s the block surface look like? You check it with a straight edge?

 

Great! Your headgaskets should be fine.

I'm thinking you just got it hot. Was the tune ever finalized? I know you said it was bled but there might have been an air pocket.