They were Heat Range 8 plugs in the car and they were fresh plugs.... I could have gone to Heat Range 9, but the issue being if I started the car from cold, stalled it while setting off, the plugs would be goosed and Id need to take them out and clean them before restarting the car. Not good for a street car! There were markings around the valve seat to suggest it was defiantly the plug that failed first and took the valve out and not vice versa... The other 3 plugs were showing signs of perfect running conditions and were perfectly intact... Ricky has been using those plugs in a range of high powered starlets and silly powered Hondas for years. I guess I'm just unlucky.... Story of my Life lol