forced induction psi standard 440?

just wondering what sort of boost a relatively standard build 440 (in the last 10 years or so) can comfortably take?

just that i have acces to an rb that's been sitting for a while, and an 871 roots blower (all used and cheap how i like em)

whilst i'm on it, what's the next step? cam, carbs, what have you seen that just works?

thanks in advance,