how do you kow if you need a head gasket replacement or a head on a 2006 chev equinox lt
Head gasket replacement or a head?
You really don't know until the heads are removed and checked, unless the crack is obvious like between the valves, then there's no need to have them checked you need new or rebuilt head. If there is no visible crack and the heads pressure test good they need to be milled to make sure they are flat, if this is not done the gaskets won't hold and you will be right back in there doing all over again.
And yes you can have both a blown headgaskets and a cracked head.