Many people have used putty knifes and lots of patience to remove stuck heads, but after spending an hour doing that, I decided there must be a better way. At first I tried using the wieght of the engine itself to help, but that wasn't enough to break decades of bonding between the head, engine and the gasket.
So, I decided to build a special tool to help pull the cylinder head off of the engine block. Tomorrow I should be ready to try it out.
It is a relatively simple device. A flat piece of thick metal with some bolts passing through it which would press down on some of the head studs, while two engine lifers placed in the #3 and #2 spark plug hole are attached firmly to the plate.
Fortunately I had a spare cylinder head lying around, so I could use that to layout the bolt pattern. The pictures below show how it was made.