You'll have to take the whole wiring harness off the intake as you have to pull the intake to unbolt it from the head. Don't even bother trying to remove the head without pulling the intake, its asking for trouble. There are no shortcuts for removing the wiring harness, you just have to follow it around and unplug everything, even the cam,crank, oil pressure sender connectors to make it easy to move around. There is a ground strap on both the front and back of the head, make sure to unbolt those, don't unbolt the rear strap from the head, just unbolt it from the firewall, its much easier.
Undo the wiring harness and move it aside, then you can unbolt the intake, if it already hasn't been off, order intake bolts and a gasket set now. Also if you haven't dont the plenum repair, order a felpro plenum gasket and if you want new plenum bolts. Soak those intake bolts in your favorite libation a day in advanced to get some of the rust broken loose. Then if they don't come out easily, don't force them, just rock them back and forth (tighten and loosen) until they break loose, snapping them isn't and automatic destruction of the heads, but snapping too many can cause issues.
Next would be pulling the valve cover, blow off all the junk first. When thats off, unbolt the rocker arms so the lifters and pushrods are no longer being compressed, and remove the pushrods. Tip: take a piece of cardboard and skewer the pushrods through it and ziptie or wire twist the rockers through the cardboard and label them, this will prevent getting them confused. Then you can undo the exhaust manifold. Order a set of exhaust bolts and studs now, those things are bound to be messed up. Don't be afraid to hammer the next size down socket on them, you don't want to round those babies off.
Once everything is off the head you can start unbolting it. I'd suggest following the reverse procedure of install to slowly let stress out of the head. That means loosening the font and rear most bolts opposite corners first, then moving your way in opposing corners fashion until you get them all out. That should give you the best chance not to crack or further crack the head. From there, it should lift off with a bit of elbow grease.