Turbo cut= snake oil. Also it says nothing about having the squish corrected, just that it was milled to increase compression.
My 250 head that has the turbo cut was milled a 1/4". After they quit sourcing the flat top piston it was set up to use it pretty much rendered the head useless. Anyone wanna buy a paper weight?
the o rings are the best way to get to the head permanently sealed? I think Permatex copper and copper gasket seal is tight!