So, as the title says I have a cracked gmpp head, and am wondering if it can be safely fixed. It has a hairline crack, bout 1/8th inch above the spark plug threads on the 4th cylinder. It's enough to fill about 2 inches worth of the spark plug area with coolant. I'm just going to go back to my stock head and get it cut for the bigger valves I have, so I want to fix the crack reliably enough to sell the head.