[351mustanger]

You can do a leak down test to check the head gasket. Just like adjusting the valves, you'll want the piston a tdc of compression stroke. Pressurize the cylnder with a low pressure (start around 50 psi). Check for air leaking in the intake (intake valve leak), exhaust (exhaust valve leak), valve cover breather (leaking rings), and last but not least the coolant fill. If the coolant has bubbles forming that is most likely the head gasket leaking.

When pressurizing the cylnder it may try to push the piston down and open a valve. Be aware that if you are holding the crank from moving with a wrench, the piston can spin the crank and smash a finger between the wrench and part of the cage.