You won't be happy at 12. You'll have to get a forged stroker motor, run meth, 24#'s of boost a ton of timing, a small shot on top of that, etc, etc.

 

12 psi on a 10.5:1 LSx is fine. Many C6s with ProChargers run 12+ with no issues and they are at 10.9:1. Good fuel and a good tune is all you need, check out the Forced Induction sections here and on CorvetteForum and you will see proof. I have not had my C6 dynoed since I swapped the 4.60" to a 4.10", but was told by many that boost should now be about 11-12.

Of course I do not condone such pursuits, and if you bend a rod or send a piston through the motor, you are on your own.

 

Here is a current thread in the Corvette Performance section:

https://ls1tech.com/forums/corvette-...-strength.html

 

12psi grocery gitter FTMFW lol