With a all out race motor big block all the way but if your talking about streetable power the LSX will make more power while being streetable. Like if you were to compare say a LSX 454 build vs a 502 BB while still being streetable the LSX would make more power and probably be lighter. If there were no limits and it was a dedicated track motor the BB would blow the LSX out of the water just due to the fact that you can get BB's past 540ci, huge solid roller cams, heads and intake. This is of course talking about NA and not FI.
BLK/BLK 1SS/RS Ordered 11-01-2009 Took delivery 12-22-2009. SOLD Feb 2015. Waiting on 6th gen LT1 SS with 8L90E.