Cylinder head studs

Trying to remove the head studs from the case, got majority out but 4 left that wont budge, tried the 2 nuts and also some heat but they not moving, any ideas?
Thanks for looking

 

more heat ,then cool a bit, penetrating oil, heat cool , etc

 

@davidoft cheers dave i will try that later, 2 of the inserts have come out as well, when i replace do they bottom out in the case or loctite and leave to set?

 

depends what inserts are used , if they look like a top hat they bottom out

 

@davidoft ill get a pic later, these are straight inserts no top hat

 

Case savers?