As a high school kid, I worked at a Mobil station in Allen Park, a suburb of Detroit. One of the owners had a '53 Hudson Hornet with the factory aluminum head. Our mechanic prepped the head for removal to do the valves. There was no prying, prodding or cussing that could make that head release from the block. Turns out, that was a common aluminum head issue. The mechanic suggested reinstalling the plugs and plug wires, and starting the engine. KABOOM, off came the head, and copious amounts of coolant. The four remaining loosely installed bolts kept the head from orbit. We laughed for a long while!