I forgot to mention: To test, pressurize each cylinder with an air gun. Obviously, make sure the cylinder is at top dead center first so that the valves are closed. Then nothing fancy - Just wrap the air gun in a rag and press hard against each a spark plug hole and give it a couple of quick puffs. You'll hear or see bubbles when you get to the cylinder near/under the blown gasket or head crack.

A blown gaset or head crack may also generate a slight leak into the combustion chamber that you won't be able to notice. If that is the case, pulling the spark plug may reveal the leak as coolant/moisture would be on one or more plugs.

Spencer