The one on the left is helicoiled. Technically, the threads didn't come out. I can guarantee the previous owner had a spark plug blow out and he repaired it with a helicoil.
Sent from my Whippled S2
Ah, ok I see. So what should I do next?
yeah they didnt install the helicoil right. The best way is to remove the head and install a new one with locktite and one that spreads the bottom of the helicoil.
I have a couple complete swaps for also...... lol