It hasn't happened yet but if my 2000 5.4 should blow a sparkplug (a co-workers 4.8 in his 2003 f-150 just blew one).. Are there a good set of aftermarket heads made?.. I know alot of people put the inserts in,and unless you do all of them, aren't the other 7 still prone to blow? If the heads are flawed wouldn't it be a better idea to replace them with a better aftermarket one, or is it a BIG job.. Maybe I'm just paranoid, and it will never happen to mine .. But I would like to be ahead of the game if it does happen....