The heads are part of the total engine strength and reason there is so many bolts per head that are also torque to yield type.

For boosted LSx engines I highly suggest the head is milled to support a metal O-ring which puts more strength pressure onto the head gasket to prevent gasket blowing out or slipping.

Being under boost the heads slightly lift up using a thicker bolts will prevent that lift.

I have suggested to my customers using boost to do this.