Use a flat bladed Screw Driver, of reasonable size and the thinner the angle the better, and carefully drive it between the head and the block, say in the front outside corner, and simply use the Screw Driver as a wedge.
This will lift the head, and not damage anything, as there are no damageable parts in this area.
It will just be the Gasket that is holding the head on.
Bruce.

When trying to pry something loose I usually go buy a Chinese or cheaper
wood chisel. Gets into tighter spaces and you don't feel bad wrecking the thing. I've used it many times and only finished off one completely. Plus it will scrape gunk nicely, a common practice with old cars.