Off with his head !
click on the pics for full size.
That good old problem of shifting the cylinder head on a Bullet engine. You'll need a couple of bits of angle iron, about 1" x 1". Drill two holes in the angle iron so that you can bolt it to the rocker cover studs on the cylinder head. Use a few nuts as spacers.
You may have to cut a few 'notches' in the angle iron so that you clear the valve gear. Then, with the aid of a few hefty "G" clamps, pull the head from above. You may have to give it a smart tap sideways once the pressure has been applied to the "G" clamps. Tap it from the exhaust port side, using a nice hardwood drift.
Of course, you could always try levering it off - providing you don't mind having a few fins missing from your cylinder barrel