You definatly don't need to o-ring your heads. My experiences with the cars I build to run the streets, is I run a standard head gasket with forced induction. Kinda works as a fuse. The head gasket will go before anything else. I'm currently running 12psi on my 289 in my lark and am just using a "napa special" headgasket. I've ran 20psi on stock type headgaskets before. Wouldn't recomend though lol. A lot of my customers don't like to go that route and want the best of the best, so when they do we run cometics. One of the motors we just finished is running 30psi, yes 30psi. And is using a cometic headgasket. Great headgaskets. Hmmm...... I should be a spokesperson for them lol.