SB vs BB who wins?

The one with the better cylinder heads wins. JMO
True, which one has more generally available high flowing heads with csa that can feed 400 ish cid especially in 6500-8500+ peak rpms range. Under 6000 it becomes more of a wash since your not asking a lot out of the heads, but bet generally most bbm won't nose over peak hp as hard as sbm stroker.