thought them airoheads were n/a for afew years now?? just posted the 308s cause some folks like them and cant find them in yards no more and if thay do chances of being cracked is good! these heads seem fair priced and im sure ant cracked, some people need to understand not every body wants or needs the baddest new aluminum heads,..or build the highest hp ether,..some times just a good healthy sbm is good enuff!!