Is this a street car? What type of fuel do you plan to run? An 8-71 on a 572ci engine and trying to make 12 to 15lbs of boost, you will need decent fuel.
No need to O-ring the heads or block. A MLS gasket will handle double that boost level. You may want to talk to a few other engine builders that have played with forced induction in the last 15 years. Unless this is a very high boost alcohol deal there is really no need to O-ring it.